A wide-band programmable radio frequency feed network

The design and fabrication of a Wide-Band programmable radio-frequency (RF) feed network is proposed. The design architecture is composed of four main stages, switching, phase shifting, amplification/attenuation and control. The proposed feed network is designed to cover a wide band from 2.5 to 6 GHz over two separate paths, one covers from 2.5 to 3 GHz and the other covers 3 to 6 GHz. Digitally controlled phase shifters are used to control the phase. A digital control unit is used to provide the required control signals for all the feed network stages. Digitally controlled wideband variable gain amplifiers are used to set the appropriate amplitude to the signal in both paths. The feed network is simulated and fabricated on an FR-4 substrate with thickness of 0.8mm. Good matching between simulation and measurement results is achieved. The measured amplitude and phase resolutions were approximately 0.55 dB and 6.4°, respectively.