(19)
(11) EP 0 197 653 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
22.06.1988 Bulletin 1988/25

(43) Date of publication A2:
15.10.1986 Bulletin 1986/42

(21) Application number: 86301617

(22) Date of filing: 06.03.1986
(84) Designated Contracting States:
AT CH DE FR GB LI NL SE

(30) Priority: 03.04.1985 CA 478332

(71) Applicant: NORTHERN TELECOM LIMITED
 ()

(72) Inventors:
  • Syrett, Barry Albert
     ()
  • Kennard, Paul Alan
     ()

   


(54) Microwave bandpass filter including dielectric resonators


(57) 57 A dielectric resonator microwave bandpass filter includes a printed circuit board (40) supported within a cut-off waveguide (10, 12), with dielectric resonators (44) and coupling loops on an upper surface of the board and a well (42) beneath the board so that the resonators are well spaced from ground planes. Tuning screws (66) beneath the resonators, and coupling adjustment screws above the board adjacent to the coupling loops and between adjacent resonators, provide for adjustments to provide desired filter characteristics within a wide range. Isolators (30) within the waveguide have ports coupled to the resonators via microstrip transmission lines comprising conductive tracks on the board and ports coupled to coaxial connectors (28) in end walls of the waveguide. The waveguide is formed from a cast body (10) and a flat lid (12).






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