| 摘要 |
1410458 Microwave filters WESTERN ELECTRIC CO 2 April 1974 [4 April 1973] 14454/74 Heading H1W [Also in Division H3] A planar microwave resonator comprises a rectangular conductive area 11 forming part of a printed circuit and capable of supporting two orthogonal standing waves. As shown, coupling lines 15, 16 aligned on the orthogonal bisectors of the rectangular resonator and capacitively coupled thereto, excite waves having directions of propagation respectively l 1 , l 2 associated with resonant frequencies # 1 , # 2 . The lines 15, 16 are mutually decoupled since each is situated at the node of the standing wave excited by the other. Line 17 situated at the corner 23 of the rectangle, will, however, couple to both waves. In the circuit shown in Fig. 5, lines 52, 53 are inductively coupled to the adjacent corners 54, 55 and both excite orthogonal waves at frequencies # 1 , # 2 , these waves being in phase. If the frequencies are close to each other, the circuit provides a bandpass filter having a bandwith equal to 2(# 1 -# 2 ). In the circuit of Fig. 6 (not shown), the coupling leads are situated at diagonally opposite corners whereby waves at frequencies # 1 , # 2 are excited in antiphase and the circuit provides a notch filter. |
