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.
