Digitally Controlled Beam-Steerable Printed Dipole Antenna

Abstract

A digitally controlled beam steerable printed dipole antenna operating in ISM band has been proposed using PIN diodes switching mechanism. The proposed antenna provides effective solution of beam steering by establishing adequate coverage in elevation plane using a single dipole element. The beam steering of antenna has been digitally controlled by varying the effective length of one dipole arm by switching the PIN diodes integrated on it. For effective digitally controlled beam steering, the DC biasing voltage applied for switching PIN diodes is regulated by Pulse Width Modulation (PWM) signal generated from STM32F407VG microcontroller through RC filter. Biasing elements for antenna is intentionally placed on back side of substrate through via to minimize the effect on radiation pattern. Peak gain of proposed antenna is measured as 4.57 dB with cross polarisation below −20 dB and scan loss less than 0.8 dB. The proposed antenna is capable of steering beam up to 45 degrees in elevation plane having 120 MHz operational bandwidth. In order to establish wide range of applications, proposed antenna is designed and tested for 2.45 GHz ISM band. The proposed antenna operates with minimal design complexity, high portability, reduced manufacturing cost, easily integrated architecture, lower parasitic losses and less space constraints due to single dipole structure with microcontroller switched PIN diodes integrated on antenna itself.