MODIFICATION AGREEMENT


         MODIFICATION AGREEMENT dated as of September 27, 2002, between Merrimac
Industries, Inc., a Delaware corporation ("Merrimac"), and Infineon Technologies
AG, a German corporation ("Infineon").

         WHEREAS, Ericsson Holding International B.V. ("Ericsson") has entered
into an agreement with Infineon whereby Ericsson and its affiliated companies
have agreed to sell the microelectronics business (excluding optosemiconductors
and power modules, but including the RF power business) of the Ericsson Group
(the "Business") to Infineon and to assign to Infineon certain agreements
between Merrimac and Ericsson;

         WHEREAS, in connection with the acquisition of the Business, Merrimac,
Ericsson and Infineon entered into that certain Consent and Waiver, effective as
of September 18, 2002, pursuant to which Merrimac consented to the assignment of
the agreements listed below, waived the application of the Merrimac's rights
plan, and made certain other representations, warranties convenants for the
benefit of Infineon with respect to the acquisition of the Business; and

         WHEREAS, in connection with the acquisition of the Business, Infineon
and Merrimac have agreed to modify and amend the following agreements as set
forth herein: (i) the Letter Agreement, dated as of April 7, 2000 and amended as
of February 1, 2002, among Merrimac, Ericsson and Ericsson Microelectronics,
A.B. (the "Letter Agreement"); (ii) the Registration Rights Agreement, dated as
of April 7, 2000, between Merrimac and Ericsson (the "April Registration Rights
Agreement"); (iii) the Subscription Agreement for Common Stock and Warrants,
dated as of October 26, 2000, between Merrimac and Ericsson (the "Subscription
Agreement"); (iv) the Common Stock Purchase Warrant, dated as of October 26,
2000, issued by Merrimac to Ericsson (the "Warrant"); and (v) the Registration
Rights Agreement, dated as of October 26, 2000, between Merrimac and Ericsson
(the "October Registration Rights Agreement").

         WHEREAS, references to line numbers in the below amendments refer to
lines in the EDGAR versions of such documents as originally filed with the SEC.

         NOW, THEREFORE, the parties hereto hereby agree as follows:

I.  Amendments to the Letter Agreement:

         1.   The text of the 52(nd) line of Section 1(a)(v) of the Letter
              Agreement is hereby amended by inserting the following words
              between the words "material" and "shall":




                                       1


                  "and all other confidential or proprietary information, which
                  information is known, or reasonably should be known or
                  expected, to be confidential or proprietary,"

         2.   The text of the 52nd line of Section 1(b)(v) of the Letter
              Agreement is hereby amended by inserting the following words
              between the words "material" and "shall":

                  "and all other confidential or proprietary information, which
                  information is known, or reasonably should be known or
                  expected, to be confidential or proprietary,"

         3.   The following text shall be added as Section 3(e):

                  "Restriction on Transfer to Certain Competitor. EHI agrees not
                   to sell, assign or otherwise transfer (hereinafter, a
                   "Transfer") any Shares to Anaren Microwave, Inc. ("Anaren"),
                   a competitor of Merrimac with its corporate office in East
                   Syracuse, New York (including any successor to the competing
                   businesses of Anaren); provided, however, that the foregoing
                   shall not apply to a Transfer to Anaren (i) as part of a sale
                   to the public pursuant to a registration statement under an
                   underwriting agreement or otherwise; provided that EHI shall
                   not make such a Transfer knowingly to Anaren; (ii) as part of
                   a sale pursuant to Rule 144 under the Securities Act in
                   brokers' transactions or transactions with market makers (as
                   defined in Rule 144); or (iii) in connection with a sale of
                   more than 50% of the shares of Merrimac."

II. Amendments to the April Registration Rights Agreement:

          1. The text of the definition of "Common Stock" in Section 1 of the
             April Registration Rights Agreement is hereby amended by inserting
             the following words after the word "share":

                    ", and shall include the common stock purchase rights under
                    the Company's Rights Agreement, dated March 9, 1999, as
                    amended from time to time, attached thereto."

          2.   The section reference to "Section 4.5" in the twelfth line of
               Section 2.1(a) of the April Registration Rights Agreement is
               hereby deleted and replaced with a reference to "Section 3.5."



                                    2


          3.   The text of the 15th line of Section 2.1(b) of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "usual and" between the words "in" and "customary."

          4.   The text of the second line of Section 2.1(d)(i) of the April
               Registration Rights Agreement is hereby amended by inserting
               the following words after the word "effective":

                   "; provided that no stop order suspending the effectiveness
                   thereof has been issued and such registration has not been
                   withdrawn or terminated (except after the period contemplated
                   by Section 2.3(a) hereof)"

          5.   The text of Section 2.1(e) of the April Registration Rights
               Agreement, incorrectly lettered 2.1(c), is hereby amended and
               restated to read in its entirety as follows:

                           "(e) Notwithstanding anything to the contrary
                   contained in any other provision of this Agreement, the
                   Company shall not be required to maintain the effectiveness
                   of a registration under the Act of an offering on a delayed
                   or continuous basis pursuant to Rule 415 (or any successor
                   provision then in force) under the Act (a "Shelf
                   Registration") at the request of the Holder pursuant to this
                   Section 2.1 for more than ninety (90) days or until all
                   Holders have completed the distribution relating thereto;
                   provided, however, that such ninety (90) day period shall be
                   extended for a period of time equal to the period the Holders
                   refrain from selling any securities included in such
                   registration at the written request of the Company in
                   accordance with Section 2.4 or an underwriter or in
                   accordance with the provisions of Section 2.13."

          6.   The section reference to "Section 4.5" in the ninth line of
               Section 2.2(a) of the April Registration Rights Agreement is
               hereby deleted and replaced with a reference to "Section 3.5."

          7.   The text of the 17th line of Section 2.2(b) of the April
               Registration Rights Agreement is hereby amended by deleting the
               first reference to the words "pro rata."

          8.   The text of the second line of Section 2.3(a) of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "on a Shelf Registration, if the Company then qualifies,
               or, if it does not then qualify for the use of a Shelf
               Registration," between the words "Statement" and "on." The text
               of the 13th line of that same section is hereby amended by
               inserting the words "or in accordance with the provisions of
               Section 2.13" after the word "underwriter."

                                       3


          9.   The text of the second line of Section 2.5 of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "to request the effectiveness of a Registration Statement"
               between the words "action" and "pursuant."

          10.  The text of the ninth line of Section 2.6(a) of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "other than those useable with respect to another
               registration proceeding" between the word "Statement" and the
               closed parenthesis. The same line of that same section is hereby
               amended by inserting the following words between the closed
               parenthesis and the comma:

                  "other than upon or after any disclosure which had or could
                  have a negative impact on the Company or the Common Stock or
                  upon or after the occurrence or the threat of the occurrence
                  of any event which had or could have a negative impact on the
                  Company, the Common Stock or the financial markets"

          11.  The text of fourth line of Section 2.6(b) of the April
               Registration Rights Agreement is hereby amended by inserting the
               following after the word "Statement":

                  "; provided however, that the Holders shall have no obligation
                  to pay their respective pro rata share of the incremental
                  registration fee payable under the Act or any blue sky fees
                  and expenses, if applicable."

          12.  The section reference to "Section 2.6(b)" in the first line of
               Section 2.7(a) of the April Registration Rights Agreement is
               hereby deleted and replaced with the a reference to "Section
               2.7(b)."

          13.  The text of the fourth line of Section 2.8 of the April
               Registration Rights Agreement is hereby amended by adding the
               words "customary and usual" in between the words "accept the" and
               "terms." The word "Company" in the 20th line of that same section
               is hereby deleted and replaced with the word "Holders".

          14.  The text of the 25th line of Section 2.10(a) of the April
               Registration Rights Agreement is hereby amended by inserting the
               clause "(and only to the extent)" between the words "extent" and
               "that." The text of the 28th line of that same section is hereby
               amended by inserting the words "for such Holder" between the
               words "underwriter" and "or controlling." The text of the 28th
               line of that same section is also amended by inserting the words
               "of such Holder or underwriter for such Holder" between the word
               "person" and the comma.

                                       4


          15.  The text of the third line of Section 2.10(b) of the April
               Registration Rights Agreement is hereby amended by inserting the
               word "and" between the comma and the word "each." The text of the
               fourth through sixth lines of the same section are hereby amended
               by deleting the clause ", any underwriter, any other Holder
               selling securities in such registration statement and any
               controlling person of any such underwriter or other Holder,". The
               text of the eighth line in that same section is hereby amended by
               inserting the following words between the comma and the word
               "insofar":

                        "including as a result of claims made by any underwriter
                    of securities included in such Registration Statement and
                    any other Holder selling securities in such Registration
                    Statement and any controlling person of any such underwriter
                    or other Holder,"

          16.  The text of the 19th line of Section 2.10(c) of the April
               Registration Rights Agreement is hereby amended by deleting the
               word "this." The text of the 20th line of that same section is
               hereby amended by inserting the clause "(a) or (b) to the extent
               of such prejudice" after the number "2.10" and before the comma.
               The text of the 22nd line of that same section is hereby amended
               by deleting the word "this" before, and inserting the clause "(a)
               or (b)" after, the number "2.10."

          17.  The text of the 16th line of Section 2.10(d) of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "or alleged omission" between the words "omission" and "to
               state."

          18.  The text of the third line of Section 2.13 of the April
               Registration Rights Agreement is hereby amended by inserting the
               words "effective date, or the" between the words "following the"
               and "date" and deleting the word "final" and replacing it with
               the words "filing of the Rule 424(b)". The fourth line of that
               same section is hereby amended by deleting the word "a" and
               replacing it with the word "such".

          19.  The text of the first line of Section 2.14 of the April
               Registration Rights Agreement is hereby amended by inserting the
               word "registration" between the words "any" and "right." The
               second line of that same section is hereby amended by deleting
               the word "after" and replacing it with the word "during."


III. Amendments to the Subscription Agreement:

          1.   The text of Section 4.1(c) of the Subscription Agreement is
               hereby amended and restated to read in its entirety as follows:

                                       5


                           "(c) Each Investor covenants that, unless the
                  Purchased Shares, the Purchased Warrants, the Underlying
                  Shares or any other shares of capital stock of the Company
                  received in respect of the foregoing have been registered
                  pursuant to the Registration Rights Agreement being entered
                  into among the Company and the Investors, such Investor will
                  not dispose of such securities unless in accordance with an
                  offering registered under the Securities Act or in accordance
                  with an exemption from such requirements and applicable Blue
                  Sky Laws."

          2.  The text of the 16th line of Section 4.2 of the Subscription
              Agreement is hereby amended by inserting the word "reasonably"
              between the words "Company" and "determines."

          3.  The text of the seventh line of Section 4.3 of the Subscription
              Agreement is hereby amended by inserting the words "as applicable"
              after the word "legend" and before the colon.

          4.  The text of the third line of Section 5.1(a) of the Subscription
              Agreement is hereby amended by deleting the words "information
              reporting forms" and replacing them with the clause "information,
              reports, and forms". The text of the 5th line of that same section
              is hereby amended by inserting the clause "(including, without
              limitation, under Rule 144 promulgated by the SEC)" after the word
              "adopted" and before the comma.

          5.  The text of the third line of Section 5.1(b) of the Subscription
              Agreement is hereby amended by inserting the words "and other
              information" between the words "report" and "of the Company."

IV. Amendments to the Warrant:

          1.  The text of the last line in the paragraph defining the term
              "Common Stock" in the Warrant, is hereby amended by inserting the
              words "and shall include the common stock purchase rights under
              the Company's Rights Agreement, dated March 9, 1999, as amended
              from time to time, attached thereto" after the closed parenthesis
              and before the period.

          2.  Section 2 of the Warrant is hereby amended and restated to read in
              its entirety as follows:

              "2. Sale or Exercise Without Registration. If, at the time of any
                  exercise, transfer or surrender for exchange of a Warrant or
                  of Underlying Securities previously issued upon the exercise
                  of Warrants, such Warrant or Underlying Securities shall not
                  be registered under the Securities Act, the Holder will not
                  dispose of such Warrant or the Common Stock issuable




                                       6






                  upon exercise unless in accordance with an offering registered
                  under the Securities Act or in accordance with an exemption
                  from such requirements and applicable state securities laws,
                  provided that the disposition thereof shall at all times be
                  within the control of such Holder or transferee, as the case
                  may be, and provided further that nothing contained in this
                  Section 2 shall relieve the Company from complying with any
                  request for registration pursuant to the Registration Rights
                  Agreement or relieve the Holder from the restrictions on
                  transfer set forth in Section 21 below. The first Holder of
                  this Warrant, by acceptance hereof, represents to the Company
                  that it is acquiring the Warrants for investment and not with
                  a view to the distribution thereof."

          3.  The text of the sixth and seventh lines of Section 3.1 of the
              Warrant is hereby amended by deleting the words "called for on the
              face of" and replacing them with the words "then issuable under."
              The text of the seventh and eighth lines of that same section are
              hereby amended by deleting the clause "(without giving effect to
              any adjustment therein)".

          4.  The text of the fifth and sixth lines of Section 3.2 of the
              Warrant is hereby amended by deleting the clause "(without giving
              effect to any adjustment therein)". The text of the twelfth and
              13th lines of that same section are hereby amended by deleting the
              words "on the face or faces thereof". The text of the 13th and
              14th lines of that same section are hereby amended by deleting the
              clause "(without giving effect to any adjustment therein)." The
              text of the 14th and 15th lines of that same section are hereby
              amended by deleting the words "called for on the face of" and
              replacing them with the words "then issuable under". The text of
              the 14th line of that same section is hereby amended by inserting
              the words "immediately prior to such partial exercise hereof"
              between the words "Warrant" and "minus."

          5.  The text of the fifth line of Section 3.3 of the Warrant is hereby
              amended by deleting the word "the" between the words "Stock," and
              "Warrant" and inserting the words "all or a portion of this". The
              text of the sixth line of that same section is hereby amended by
              deleting the word "Certificate". The text in the eighth line of
              that same section is hereby amended by inserting a comma after the
              word "Warrants" appearing for the second time in that line, and by
              deleting the word "or" following the word "Warrants" appearing for
              the second time in that line. The text in the ninth line of that
              same section is hereby amended by inserting the words "or other
              securities" between the words "Stock" and "to be." The text of the
              13th line is hereby amended by inserting the clause "Warrants,"
              between the words "number of" and "shares."

          6.  The text of the eleventh line of Section 3.4 of the Warrant is
              hereby amended by deleting the word "ten" and replacing it with
              the word "five." The text of



                                       7





              the twelfth line of that same section is hereby amended by
              inserting the word "reasonably" between the words "be" and
              "determined."

          7.  The text of the fifth and sixth line of Section 3.6 of the Warrant
              is hereby amended by inserting the words "immediately prior to"
              between the words "until" and "the consummation of such
              transaction."

          8.  The text of the second line of Section 5(a)(i) of the Warrant is
              hereby amended by inserting the words "or distribution" after the
              word "dividend" and before the comma.

          9.  The text of the second line of Section 5(a)(iii) of the Warrant is
              hereby amended by inserting the words "stock split," after the
              clause "split-up," and before the word "reclassification." The
              third line of the that same section is hereby amended by inserting
              the clause ", reverse stock split" after the word "shares."

          10. The text of Section 5(b) of the Warrant is hereby amended and
              restated to read in its entirety as follows:

                    "The Purchase Price and the Dilution Price shall be
                  equitably adjusted from time to time at the time of the
                  occurrence of an adjustment pursuant to Section 5(a) above or
                  Section 6 below and, in addition, as the Board of Directors,
                  in good faith, reasonably determines to be otherwise necessary
                  to protect the interest of the Holder of the Warrant."

          11. The text of the third line of Section 6 of the Warrant is hereby
              amended by inserting the words "sell or" before the word
              "transfer." The text of the fourth and fifth lines of that same
              section is hereby amended by deleting the words "under any plan or
              arrangement contemplating the dissolution of the Company." The
              eighth line of that same section is hereby amended by deleting the
              word "dissolution" and replacing it with the words "sale or
              transfer". The 13th line of that same section is hereby amended by
              deleting the word "dissolution" and replacing it with the word
              "transaction." The 16th line of that same section is hereby
              amended by inserting the clause ", transfer" in front of the word
              "merger." The text of the 19th line of that same section is hereby
              amended by deleting the word "purchasing" and replacing it with
              the word "acquiring". The text in the 24th line of that same
              section is hereby amended by deleting the words "Section 6" and
              replacing them with the word "Warrant."

          12. The text of the last line of Section 7.1 of the Warrant is hereby
              amended by inserting the words "or increased" after the word
              "reduced."

                                       8


          13. The text of the third line of Section 7.2(a) of the Warrant is
              hereby amended by deleting the words "date hereof" and replacing
              them with the words "Original Issue Date".

          14. The text of the ninth and 13th lines of Section 7.2(b) of the
              Warrant are hereby amended by inserting the words "for all then
              unexercised Warrants" between the words "share" and "shall." The
              16th line of that same section is hereby amended by inserting the
              words "those actually" between the words "were" and "issued." The
              text of the last line of that same section shall be amended by
              inserting the words "but in no event shall the Purchase Price be
              increased above what the Purchase Price was prior to the
              adjustment(s) contemplated by this Section 7.2(b)" after the word
              "exchanged" and before the period.

          15. The text of the third line of Section 7.3(a) of the Warrant is
              hereby amended by inserting the words "or Convertible Securities"
              after the word "Stock."

          16. The text of the ninth and twelfth lines of Section 7.3(b) of the
              Warrant are hereby amended by inserting the words "for all then
              unexercised Warrants" between the words "share" and "shall." The
              text of the 15th line of that same section is hereby amended by
              inserting the word "actually" between the words "those" and
              "issued." The text of the last line of that same section is hereby
              amended by inserting the words "but in no event shall the Purchase
              Price be increased above what the Purchase Price was prior to the
              adjustment(s) contemplated by this Section 7.3(b)" after the word
              "exercised" and before the period.

          17. The text of Section 7.4 of the Warrant shall be deleted in its
              entirety and be restated as follows: "7.4. Intentionally Omitted."

          18. The text of the eighth line of Section 7.5 of the Warrant is
              hereby amended by deleting the words "date hereof" and replacing
              them with the words "Original Issue Date".

          19. The text of the sixth and seventh lines of Section 7.6 of the
              Warrant are hereby amended by deleting the word "reasonably" in
              the seventh line and inserting the word "reasonably" in the sixth
              line after the clause "good faith,". The text of the eleventh line
              of that same section is hereby amended by deleting the words
              "other stock" and replacing them with the words "Other Securities
              or other assets." The text of the 13th line of that same section
              is hereby amended by inserting the word "reasonably" between the
              clause "faith," and the word "determines." The text of the 20th
              line of that same section is hereby amended by inserting the words
              "or other assets" between the words "Securities" and "issuable."
              The text of the 23rd line of that same section is hereby amended
              by inserting the clause ", decrease the Dilution Price," after the
              words "per share." The text of the last line of Section 7.6 is

                                       9


              hereby amended by inserting the words "or other assets" after the
              word "Securities."

          20. The text of the sixth line of Section 7.7 of the Warrant is hereby
              amended by inserting the clause "(subject to adjustments thereto
              for any of the events contemplated by Sections 5, 6 and/or 7
              above)" after the words "Issue Date."

          21. The text of the third line of Section 9 of the Warrant is hereby
              amended by inserting the words "or other assets" after the word
              "Securities."

          22. The text of the seventh line of Section 10 of the Warrant is
              hereby amended by deleting the word "capital." The text of the
              ninth line of that same section is hereby amended by inserting the
              words "or sale" after the word "transfer." The text of the
              eleventh line of that same section is hereby amended by inserting
              the words "or any similar transaction" after the word "Company."

          23. The text of the fourth line of Section 11 of the Warrant is hereby
              amended by inserting the words "and other assets" after the word
              "Securities."

          24. The text of the third line of Section 15 of the Warrant is hereby
              amended by inserting the words "or other assets" after the word
              "Securities" and before the closed parenthesis.

          25. The text of the last line of Section 16 of the Warrant is hereby
              amended by inserting the words "without posting a bond or other
              security or proving the likelihood of success" after the word
              "otherwise" and before the period.

          26. The text of the 16th line of Section 21(b) of the Warrant is
              hereby amended by inserting the word "reasonably" after the word
              "Company."

V. Amendments to the October Registration Rights Agreement:

          1.  The text of the definition of "Common Stock" in Section 1 of the
              October Registration Rights Agreement is hereby amended by
              inserting the following words after the word "share":

                    ", and shall include the common stock purchase rights under
                    the Company's Rights Agreement, dated March 9, 1999, as
                    amended from time to time, attached thereto."

          2.   The text of the 15th and 16th lines of Section 2.1(b) of the
               October Registration Rights Agreement is hereby amended by
               inserting the words "usual and" between the words "in" and
               "customary."

                                       10


          3.   The text of the fifth line of Section 2.1(d)(i) of the October
               Registration Rights Agreement is hereby amended by inserting the
               following words after the word "effective":

                   "; provided that no stop order suspending the effectiveness
                   thereof has been issued and such registration has not been
                   withdrawn or terminated (except after the period contemplated
                   by Section 2.3(a) hereof)"

          4.   The text of Section 2.1(e) of the October Registration Rights
               Agreement is hereby amended and restated in its entirety to read
               as follows:

                           "(e) Notwithstanding anything to the contrary
                   contained in any other provision of this Agreement, the
                   Company shall not be required to maintain the effectiveness
                   of a registration under the Act of an offering on a delayed
                   or continuous basis pursuant to Rule 415 (or any successor
                   provision then in force) under the Act (a "Shelf
                   Registration") at the request of the Holder pursuant to this
                   Section 2.1 for more than ninety (90) days or until all
                   Holders have completed the distribution relating thereto;
                   provided, however, that such ninety (90) day period shall be
                   extended for a period of time equal to the period the Holders
                   refrain from selling any securities included in such
                   registration at the written request of the Company in
                   accordance with the provisions of Section 2.4 or an
                   underwriter or in accordance with the provisions of Section
                   2.13."

          5.   The text of the 18th line of Section 2.2(b) of the October
               Registration Rights Agreement is hereby amended by deleting the
               first reference to the words "pro rata."

          6.   The text of the second line of Section 2.3(a) of the October
               Registration Rights Agreement is hereby amended by inserting the
               words "on a Shelf Registration, if the Company then qualifies,
               or, if it does not then qualify for the use of a Shelf
               Registration," between the words "Statement" and "on." The text
               of the 13th line of that same section is hereby amended by
               inserting the words "or in accordance with the provisions of
               Section 2.13" after the word "underwriter."

          7.   The text of the second and third lines of Section 2.5 of the
               October Registration Rights Agreement is hereby amended by
               inserting the words "to request the effectiveness of a
               Registration Statement" between the words "action" and
               "pursuant."

          8.   The text of the tenth line of Section 2.6(a) of the October
               Registration Rights Agreement is hereby amended by inserting the
               words "other than those useable with respect to another
               registration proceeding" between the word "Statement" and the
               closed parenthesis. The same line of that same section


                                       11





               is hereby amended by inserting the following words between the
               closed parenthesis and the comma:

                  "other than upon or after any disclosure which had or could
                  have a negative impact on the Company or the Common Stock or
                  upon or after the occurrence or the threat of the occurrence
                  of any event which had or could have a negative impact on the
                  Company, the Common Stock or the financial markets"

          9.   The text of the fifth line of Section 2.6(b) of the October
               Registration Rights Agreement is hereby amended by inserting the
               following after the word "Statement":

                  "; provided however, that the Holders shall have no obligation
                  to pay their respective pro rata share of the incremental
                  registration fee payable under the Act or any blue sky fees
                  and expenses, if applicable."

          10.  The section reference to "Section 2.6(b)" in the second line of
               Section 2.7(a) of the October Registration Rights Agreement is
               hereby deleted and replaced with the a reference to "Section
               2.7(b)."

          11.  The text of the fourth line of Section 2.8 of the October
               Registration Rights Agreement is hereby amended by adding the
               words "customary and usual" in between the words "accept the" and
               "terms."

          12.  The text of the 25th line of Section 2.10(a) of the October
               Registration Rights Agreement is hereby amended by inserting the
               clause "(and only to the extent)" between the words "extent" and
               "that." The text of the 28th line of that same section is hereby
               amended by inserting the words "for such Holder" between the
               words "underwriter" and "or controlling." The text of the 28th
               line of that same section is hereby amended by inserting the
               words "of such Holder or underwriter for such Holder" between the
               word "person" and the comma.

          13.  The text of the third line of Section 2.10(b) of the October
               Registration Rights Agreement is hereby amended by inserting the
               word "and" between the comma and the word "each." The text of the
               fourth through sixth lines of the same section are hereby amended
               by deleting the clause ", any underwriter, any other Holder
               selling securities in such registration statement and any
               controlling person of any such underwriter or other Holder,". The
               text of the ninth line in that same section is hereby amended by
               inserting the following words between the comma and the word
               "insofar":

                                       12


               "including as a result of claims made by any underwriter of
               securities included in such Registration Statement and any other
               Holder selling securities in such Registration Statement and any
               controlling person of any such underwriter or other Holder,"

          14.  The text of the 20th line of Section 2.10(c) of the October
               Registration Rights Agreement is hereby amended by deleting the
               word "this." The text of the 21st line of that same section is
               hereby amended by inserting the clause "(a) or (b) to the extent
               of such prejudice" after the number "2.10" and before the comma.
               The text of the 23rd line of that same section is hereby amended
               by deleting the word "this" and inserting the words "(a) or (b)"
               after the number "2.10."

          15.  The text of the 16th line of Section 2.10(d) of the October
               Registration Rights Agreement is hereby amended by inserting the
               words "or alleged omission" between the words "omission" and "to
               state."

          16.  The text of the fourth line of Section 2.13 of the October
               Registration Rights Agreement is hereby amended by inserting the
               words "effective date, or the" between the words "following the"
               and "date" and deleting the word "final" and replacing it with
               the words "filing of the Rule 424(b)". The fifth line of that
               same section is hereby amended by deleting the word "a" and
               replacing it with the word "such".

          17.  The text of the second line of Section 2.14 of the October
               Registration Rights Agreement is hereby amended by inserting the
               word "registration" between the words "any" and "right." That
               same line of that same section is hereby amended by deleting the
               word "after" and replacing it with the word "during."

Except as expressly amended herein, each of the Letter Agreement, Warrant (as
heretofore amended), April Registration Rights Agreement, Subscription Agreement
and October Registration Rights Agreement shall remain in full force and effect.

This Modification Agreement shall be governed by, and construed and interpreted
in accordance with, the laws of the State of New York, without giving effect to
any conflict of law provisions thereof. This Modification Agreement may not be
amended, supplemented or modified nor may the obligation of the parties hereto
be waived, except by an instrument in writing signed by each of the parties
hereto. This Modification Agreement may be executed in any number of
counterparts each of which when so executed shall be deemed an original and all
of which counterparts together shall constitute one and the same instrument.


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         IN WITNESS WHEREOF, the parties hereto have duly executed this
Modification Agreement as of the day first above written.


                                 MERRIMAC INDUSTRIES, INC.



                                 By:/s/ Mason N. Carter
                                    ---------------------------------------
                                     Name:  Mason N. Carter
                                     Title: Chairman and
                                            Chief Executive Officer


                                 INFINEON TECHNOLOGIES AG



                                 By: /s/ Bogel
                                     -------------------------------------
                                     Name:  Bogel
                                     Title: Corporate Legal Counsel



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