VHF Monolithic Filters.
Quarterly rept. no. 2, 15 Jan-15 May 72,
PIEZO TECHNOLOGY INC ORLANDO FL
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This program deals with improvements in VHF monolithic crystal filters in the 100 to 250 MHz frequency range. Efforts will be directed toward minimizing the need for spreading coils and extending the practical number of poles to eight. The value of the maximum inductorless bandwidth, expressed as a percentage of center frequency, depends upon both the resonator capacitance ratio and the magnitude of the stray capacitance present. Special packaging techniques are under investigation to achieve the requirement for low stray capacitance. Components of a tandem monolithic package affording reduced stray capacitance and hence making possible increased pass bandwidth are described. Final assembly of a prototype filter will be completed in the next quarter. Experimental work at 111.455 MHz is reported on multi-resonator monolithic and tandem monolithic crystal filters using third overtone plates. A four-pole monolithic filter with a 3 db bandwidth in excess of 40 kHz was successfully fabricated in an HC-18 size envelope. Author
- Electrical and Electronic Equipment