Design and modeling of an output microwave filter for S band primary radar transmitter

In this paper a design of an output microwave filter for S band primary radar transmitter is described. Filter is realized by microstrip technology. The article presents two types of microwave filters. The first type is a band-pass filter; the second one is a low-pass filter. It is very difficult to achieve a low filter insertion loss in the passband, while maintaining a sufficient spurious signal suppression in the restraint band. Finally the low pass filter was chosen for implementation. The implemented filter insertion loss is below 0.3 dB and the restraint band attenuation is above the 35 dB. Since the resonant elements are small, filter dimensions are compact. Simulations results of the both filters are presented. In the case of the low-pass filter the simulated and experimentally verified parameters are compared.