A compact design of switched line phase shifter for a microstrip phased array antenna

This paper presents a 1×4 microstrip Phased Array Antenna (PAA) with a uniquely designed switch line phase shifter to obtain steerable beam pattern. The antenna is designed on a Rogers RT/Duroid 6006^TM dielectric substrate with a relative permittivity of 6.15. Each element of the probe fed PAA are connected to a phase shifter on a different dielectric substrate. The phase shifter has four equal length microstrip lines placed on a circular fashion around a via that connects the antenna. The circular phase shifter network feeds the antenna through the via at the center. This design is useful if a phase shifter must be integrated with an antenna in a tight space. A diode switch is placed between the microstrip traces to change the length of the transmission line. An addition of each transmission line provides a phase shift of 90°. The Arduino controlled switches can be turned ON and OFF to steer the antenna beam pattern. The maximum steering angle obtained was ±45°. The antenna is appropriate for Wi-Fi application that requires directional beam pattern, Multiple Input Multiple Output (MIMO) communications, scanning radar, and other applications requiring steerable beam pattern.