16-port array antenna feeding network with programmable phase shifter capability

The development of a 16-port array antenna feeding network with programmable phase shifter capability is presented. The feeding network which is designed based on T-junction power divider is deployed on an FR4 Epoxy dielectric substrate with the thickness of 1.6mm and the dimension of 96.4mm × 600mm. The mechanism of phase shifter for each port is carried out by using a variable capacitor (varactor) diode by controlling its reverse bias voltage through a microcontroller. The distributed phase shifter is located at a separated 50Ω transmission line of each port. By using a buck converter equipped with optocoupler to isolate a control signal obtained from microcontroller, the programmable phase shifter is optimized to shift the phase of each port independently. From the characterization result, it demonstrates that the phase of each output port at the same frequency tends to have similar value each other with the average value of 94.89°.