Published 12 issues per year
ISSN Print: 0040-2508
ISSN Online: 1943-6009
Indexed in
Filters on the Acoustical Surface Waves with Combined Single-and Dual-Mode Sections
ABSTRACT
Filter structures on the acoustical surface waves (ASWs) with small insertion losses with combined elementary ladder or balance-bridge sections on single-mode single-input resonators (LDR or BBR) and dual-mode sections on longitudinally connected resonators (LCRs) are described. Such combinations of single- and dual-mode sections allow operation at interim or carrier filter frequencies with axial or balance loads of 50−300 Ω with insertion losses IL = 2.3−3.8 dB, without using additional matching circuits and higher attenuation in the attenuation band up to UR = 55−70 dB in a broad frequency band. Problems of matching of elementary sections for reduction of distortions due to reflections have been analyzed. Examples of filters on ASWs with LDR−LCR−LDR; LCR−LDR−LCR; LCR−BBR−LCR; LDRBBR structures for frequencies of 442, 484, 135, 105, and 160 MHz are given.