HF TUNABLE FILTERS.
AIRBORNE INSTRUMENTS LAB DEER PARK N Y
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An investigation to advance the state of the art in narrow-band, high power 2 to 30 Mc filters resulted in the realization of the elliptic-function filter response using transmission-line techniques. An analysis performed on this program showed the elliptic-function filter to be of substantially lower loss than conventional filters with monotonic attenuation band characteristics. Curves were prepared, with the aid of a computer, relating the midband insertion loss to the other response characteristics for the elliptic function filter. Design equations are presented for the transmission-line resonators and coupling structures in the elliptic-function filter. Several experimental filters using helical resonators were constructed and evaluated with the measured results showing close agreement with theory. The lower loss characteristic of the elliptic-function filter as compared with conventional filters was verified experimentally. Various tuning techniques were evaluated and a capacitively tuned experimental model covered a one-octave frequency band with only a small increase in loss due to tuning. Author
- Electrical and Electronic Equipment