NON-REFLECTING BRANCHING FILTER 



91 



equivalent series resonant circuit continuously from infinity down to any value 

 within the range required. 



It should be pointed out that impedance and frequency adjustments are not 

 in practice completely independent, but do at least permit the realization of 

 any required value. Furthermore, mutual coupling between the probes inter- 

 feres with the exact realization of the circuits of Fig. 7. This coupling does 

 not interfere, however, with the realization of satisfactory filter character- 

 istics. 



(a) LUMPED CIRCUIT EQUIVALENT 



T 



i 



(b) LUMPED CIRCUIT PLUS 

 TRANSMISSION-LINE EQUIVALENT 



Fig. 7 — Band reflection filter. 



IMPEDANCE LEVEL 

 ADJUSTED BY TOP SCREWS 



"-FREQUENCY ADJUSTED 

 BY SIDE SCREWS 



Fig. 8 — Waveguide band reflection filter. 



When the reflection filter of Fig. 7 was embodied in waveguide form through 

 use of the series resonant circuits just described, the configuration illustrated 

 in Fig. 8 resulted. It was found that, with the exception of a slight change in 

 disk to guide wall spacing, a single configuration could be tuned to any of the 

 desired channels. 



Electrical Performance 



Individual components as described above were constructed, adjusted and 

 assembled to form a five-channel branching network (Fig. 9). The electrical 

 performance of this network was trimmed systematically, then was measured 



