Multi mode Resonator based Concurrent Triple band Band pass Filter with Six Transmission Zeros for Defence Intelligent Transportation Systems Application

Abstract

A compact and highly selective triple-band bandpass filter (BPF) is designed and presented in this paper. Proposed filter offers low insertion loss, and passband characteristics is achieved by using two coupled MMR multi-mode resonators (MMR1 and MMR2) and an inverted T and circular shape MMRs. The filter operates at frequency 2.43 GHz (Vehicular Communication), 5.91 GHz (ITS band), and 8.86 GHz (satellite communication band). The simulation and measurement results show a minimum insertion loss of 1.6 dB, 0.73 dB, and 2.8 dB for triple-band BPF. The return loss is found to be greater than 13.06 dB, 28.6 dB, and 21.55 dB. It is noted that measurement results are in accordance with the result of electromagnetic simulation. Desired triple-band multi-mode resonators (MMRs) filter characteristics are achieved with six transmission zeroes (TZs). The filter comprises of MMRs which provide small size and control over the spurious frequency. By using a parallel-coupled microstrip line, the first and third passbands are realised. Whereas by using an end-coupled microstrip line, the second passband is recognised. At the input and output ports, the resonator coupling technique is used. By using the anti-parallel microstrip line arrangement, the transmission zero is acquired. The dimensions of the designed filter are 25×16 mm 2.