A Novel C Band Transmit Reject Filter for VSAT Transceiver

VSATs are extremely advantageous stations that can send and receive data to or from a satellite at any location without any explicit on-site infrastructure. They are therefore perfect for mounting on vehicles and enabling communication even in the worst circumstances. Transmit reject filter (TRF) provides necessary isolation between transmit and receive chains. Basic requirements for a TRF include low insertion loss in the passband, compact size, and high rejection in transmit band. Typically, X-band, Ku-band, or Ka-band frequencies are used by VSATs. However, in regions where severe weather conditions, such as torrential rain, can corrupt signals, C-band VSATs are used. In this research work, we propose a novel C band transmit reject filter for VSAT transceivers. The proposed design achieves low passband insertion loss and highly spiky stopband rejection that is required for high-speed VSAT systems. This paper describes the realization and development of a C-band TRF based on waveguide technology. The design is based on 21st order waveguide filter with transmission zeros placed at a cut-off frequency to enhance rejection in the stop band and has a roll-off factor of 150 dB/GHz.