Varactor-tuned microstrip-patch antenna with frequency and polarisation agility

Abstract

A new design of a microstrip-patch antenna reconfigurable by means of varactors is presented. The antenna consists of multiple smaller patches connected by varactors that allow frequency tuning, polarisation agility and phase shifting while maintaining good impedance matching. The antenna design does not include any critical ‘via’ connections to the microstrip ground layer. A prototype was fabricated and tested in the L-band frequency range. The obtained frequency-tuning range is from 890 to 1500 MHz with good impedance matching. The polarisation could be adjusted linearly in an arbitrary direction with 180° phase-reversal option.