A Novel Compact Design of Filters and Diplexers with Metal Housing Having Complicated Cross Section

A novel design of the strip-line filters and diplexers of the base station antennas operating within frequency bands 824-880/900-960 MHz, 1710-1830/1885-2025 MHz and 1710-1880/1920-2170 MHz is proposed. The filters and diplexers have simple design since their all-metal strip-lines are fabricated as an entire piece of metal plate by punching technology. The suggested design of filters/diplexers doesn't contain tuning screws and the tuning procedure is not required. As a result, the proposed filters/diplexers have the easy-to-manufacture repeatable design which is suitable for the low-cost mass production. The filters are matched with standard 50 Ohm coaxial cable providing S11
$< -20$
dB and insertion loss is -0.35 dB within passband. The stop-band attenuation is better than - 20 dB. The reflection loss of diplexer is -19 dB, isolation between outputs is better than -26dB, insertion loss of both frequency bands is -0.55 dB. Thus, the proposed filters/diplexers are promising candidates for base station applications.