(19)
(11) EP 0 456 207 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
25.11.1992 Bulletin 1992/48

(43) Date of publication A2:
13.11.1991 Bulletin 1991/46

(21) Application number: 91107478.9

(22) Date of filing: 08.05.1991
(51) International Patent Classification (IPC)5: H01P 5/02
(84) Designated Contracting States:
DE FR GB NL SE

(30) Priority: 09.05.1990 JP 119533/90

(71) Applicant: SUMITOMO ELECTRIC INDUSTRIES, LIMITED
Osaka 541 (JP)

(72) Inventor:
  • Shiga, Nobuo, c/o Yokohama Works of
    Sakae-ku, Yokohama-shi, Kanagawa (JP)

(74) Representative: Lehn, Werner, Dipl.-Ing. et al
Hoffmann, Eitle & Partner, Patentanwälte, Postfach 81 04 20
81904 München
81904 München (DE)


(56) References cited: : 
   
       


    (54) Input matching circuit and method for adjusting the same


    (57) An input matching network in an input circuit of an amplifier comprises a basic input matching circuit (50) including a serial inductance, a strip line of an approximately quarter wavelength connected in series to the basic matching circuit, and a parallel capacitance including an open stub (S1) connected between the strip line and the basic input matching circuit (50). An electrical length (lε) of the open stub (S1) is selected such that a phase angle of a signal source reflection coefficient as viewed from the amplifier is larger than a mean value of manufacturing variations of a phase angle of an optimum signal source power reflection coefficient of the amplifier. By shortening the electrical length (lε) of the open stub (S1) by cutting it by a laser, a matching point can be adjusted to comply to substantially entire distribution of the manufacturing variations of the optimum signal source power reflection coefficient of the amplifier.






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