In this paper, we present the compact bandpass cavity filters for UHF range. We investigate the properties of coaxial resonators with various numbers of tubular posts from one to four. We show that the resonant frequency can be four times smaller for the four-post resonator in comparison with the single post resonator with the same cavity dimensions. We synthesized and manufactured fifth-order bandpass cavity filter on four-post coaxial resonators for the 690–806 MHz frequency range with 20-dB return loss. The filter dimensions were 30 mm × 44 mm × 127 mm. We also synthesized and manufactured the fifth-order bandpass cavity filter on four-post coaxial resonators with inductive and capacitive cross-coupling between first and fifth resonators to provide transmission zeros in amplitude–frequency characteristic in lower- and upper-frequency band, respectively. Comparison with the standard double-post coaxial cavity filters demonstrates more than 30% volume reduction with similar transmission characteristics.

在本文中，我们介绍了用于UHF范围的紧凑型带通腔滤波器。我们研究具有从一到四个不同数量的管状柱的同轴谐振器的特性。我们表明，与具有相同腔尺寸的单柱谐振器相比，四柱谐振器的谐振频率可以小四倍。我们在690-806 MHz频率范围上合成和制造了四支柱同轴谐振器上的五阶带通腔滤波器，并具有20dB的回波损耗。过滤器尺寸为30毫米×44毫米×127毫米。我们还合成并制造了四支柱同轴谐振器上的五阶带通腔滤波器，并在第一和第五谐振器之间进行了电感和电容交叉耦合，从而在低频和高频频段中提供了振幅频率特性的传输零点，分别。与标准双柱同轴腔滤波器的比较表明，具有相似的传输特性，体积减少了30％以上。