| 摘要 |
1355098 Rejection filters A KATHREIN SNR 18 Aug 1971 [21 Aug 1970] 38697/71 Heading H1W A high-frequency band rejection filter comprises a transmission line element extending between input and output 11, 11<SP>1</SP>, two (or more) shunt elements 12, 13 series resonant at the rejection frequency or frequencies, and at least one quarter-wavelength (nominally) transforming section 14 electrically equivalent to a T-section filter for matching the impedances of the shunts to that of the line. The conditions for matching are discussed in the Specification. The shunt circuits may consist of resonant lines K1, K3, off-tuned inductively, in series with respective capacitances C1, C4. Each may be realized by a resonator 31, 32, Fig. 8, of, e.g. coaxial or printed-circuit construction, coupled by stray capacitance (providing C1, C4) to the uninterrupted line conductor 34. The transforming section similarly includes an inductively offtuned resonant section K2 and series capacitances C2, C3. This is realized in the manner shown in Fig. 7 where the resonator 24 is coupled to the interrupted line 25, 26 by capacitances between the inner conductor 29 and electrodes 27, 28 attached to the line. The resonators may be capacitatively tuned and the capacitances C1, C2, C3, C4 may be adjusted by moving slugs or electrodes attached to the transmission line. A modification is referred to (Fig. 2, not shown) in which all the reactances are reversed in sign. |
