Exhibit 99.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 I, Tamer Husseini, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Annual Report of Celeritek, Inc. on Form 10-K for the fiscal year ended March 31, 2003 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Annual Report fairly presents in all material respects the financial condition and results of operations of Celeritek, Inc. By: /s/ TAMER HUSSEINI ------------------------- Name: Tamer Husseini ---------------------- Title: Chief Executive Officer I, Margaret Smith, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Annual Report of Celeritek, Inc. on Form 10-K for the fiscal year ended March 31, 2003 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Annual Report fairly presents in all material respects the financial condition and results of operations of Celeritek, Inc. By: /s/ MARGARET E. SMITH --------------------------- Name: Margaret E. Smith ------------------------- Title: Chief Financial Officer