Electronically Reconfigurable Microstrip Array Antenna with Reflective Phase Shifters at Ku Band

Abstract

An electronically reconfigurable printed array antenna at Ku band is presented in this work. A reflection-type phase shifter is proposed as electronically tunable component in order to provide reconfigurability to the array antenna. The phase shifter is based on a 3dB/90deg hybrid coupler and two identical reflective circuit with variable capacitances or varactors controlled by a DC bias voltage. Therefore, the entire input signal is redirected to the output port and its phase can be varied depending on the selected capacitance value. On the other hand, a double stacked circular patch has been designed as single radiating element achieving matching bandwidth levels higher than 8%. Several prototypes have been manufactured and measured in order to experimentally validate the simulated designs. Then, a four-element array antenna has been implemented by using a uniform microstrip power divider as feeding network. Several reflective phase shifters are integrated into the feeding network in order to provide an electronically phase variation of the electric field radiated by each array element. Thus, the microstrip array antenna achieves a continuous main beam scanning from −14 to +14 deg as well as realized gain levels higher than 13.0 dB or radiation efficiencies higher than 80%.