Circularly Polarized Microstrip Patch Array Antenna for Satellite Applications: An Approach Using Simple Feed Network

Abstract

Microstrip antennas, among various types of antennas, offer considerable ad vantages over traditional microwave antennas and are consequently utilized in numerous practical applications. Circularly polarized (CP) microstrip patch ar ray antennas offer numerous benefits, such as reduced sensitivity to polarization orientation, the capability to counteract the ionosphere’s Faraday rotation effect, enhanced resistance to interference, and improved long-distance transmission. Consequently, they play a crucial role in radar systems, satellite communica tions, GPS, and various other applications. Furthermore, a reconfigurable an tenna functions as a multifunctional apparatus, yielding a more compact and efficient design while also reducing expenses. Polarization reconfigurable anten nas can switch between various polarization modes, including LP, LHCP, and RHCP. This thesis presents the construction of a 2×2 dual-sense circularly po larized octagonal-shaped microstrip array antenna, followed by the integration of pin diodes to achieve reconfigurable circular polarization for the Ku-band fre quency suitable for satellite communication. Both antennas have a single in put feed and utilize dual-sided microwave integrated circuit (MIC) technology to enhance design flexibility and simplify the bias control circuit, resulting in a straightforward feeding circuit for the antenna. Each segment of the array is stimulated orthogonally. The switching mechanism is regulated by a single-pole double-throw (SPDT) switch composed of two PIN diodes integrated within a λ/2 delay line. The simulated outcomes indicate that the antenna may alternate between RHCP and LHCP, showcasing proficient circular polarization perfor mance. The simulated findings demonstrate excellent circular polarization (CP) performance, with a relative power level difference of 30 dB and an ARBW of 400 MHz. The array demonstrates effective impedance matching, featuring an impedance bandwidth of 1600 MHz. The gain, directivity, and efficiency find ings indicate that the antenna effectively transmits a highly focused beam in the broadside direction.