Compact Single Feed Dual Band Microstrip Patch Antenna with Adjustable Dual Circular Polarization

Abstract

This paper presents a novel dual-band, half E-shaped microstrip patch antenna (HEMSPA) with dual sense polarization. The proposed antenna covers two different frequency bands and radiates electromagnetic waves with left hand circular polarization (LHCP) and right hand circular polarization (RHCP) at lower and upper frequency bands, respectively. The dual frequency is realized by etching four T slits close to the radiating edges of HEMSPA. A shorting bar is adopted to attain LHCP waves at lower band while a vertical slot etched in the patch center aids in achieving RHCP waves at upper band. The proposed antenna has a small frequency ratio of 1.2 and good scalability. It can be easily re-designed for other operating frequencies with dual sense circular polarization (CP) or same sense CP at dual frequencies. The simulated reflection coefficient, axial ratio, and radiation pattern characteristics show a good agreement with the experimental data for dual-band performance. The measured −10 dB impedance bandwidth, 3 dB axial ratio bandwidth, and boresight gain are observed to be 1010 MHz, 70 MHz, 9.27 dBic and 120 MHz, 69 MHz, 6.63 dBic in the lower band, and upper band, respectively. The proposed antenna would be promising for modern wireless communication system applications.