UC Irvine

The phased array antennas (PAAs) are indispensable for satellite communications (SATCOM), battlefield applications, 5G communications and different other developing technological applications. The recent advances of commercial silicon beamforming chipsets have aided the pervasive employment of phased array antennas for commercial applications. This research work is focused on the design and development of phased array antennas that fulfill the growing demands of high-gain beam steering antennas in satellite and wireless communications.In the first project of this thesis, investigations on the heat sink property of a 4x2 wideband dual linear polarized phased array antenna comprised of 3D metal printed all metallic radiators, serving also as a heat sink, is presented for X-band frequency. This radiating element resembles heat fins, and is designed to cover 8.5-11.5 GHz impedance bandwidth. Excellent radiation pattern with low cross-polarization is obtained over the entire bandwidth, while the peak broadside gain is varying between 11-14 dBi. Beam scans are viable ±50° in φ=00 plane and ±30° in φ=900 plane. The beamforming network (BFN) is comprised of commercial silicon Radio Frequency Integrated Circuit (RFIC) chips which have been integrated with the antenna aperture. The temperature reduction of 60°C is achieved with the heat sink structure when the temperature distribution of BFN with and without heat sink are compared for the 4x2 array. In the second project, a wideband (22-28 GHz), polarization reconfigurable (horizontal (X-), vertical (Y-), left-hand circular and right-hand circular polarizations), flat panel, 8x8 transmit (Tx)/receive (Rx) phased array antenna (PAA), with RFIC based integrated BFN, is proposed. The array offers a realized gain of 22-23 dBi/dBic in the broadside direction and scans to approximately ±50° while maintaining 3dB gain drop/scan loss, low cross-polarized fields, and axial ratio (AR) below 3dB (in case of circular polarization (CP)) over the entire bandwidth within the given scan range. The array is comprised of novel radiating elements, arranged in a unique way in the array such that the benefit of element mirroring is achieved during the dual linear cases, whereas the benefit of sequential rotation of elements is achieved in dual CP cases. The simulated results are validated through the measurement results for a fabricated PAA prototype for the scanned radiation patterns for all four polarizations in receive mode, antenna gain-to-noise temperature (G/T) in receive mode, and effective isotropic radiated power (EIRP) in transmit mode. SATCOM employs reflector antennas with circularly polarized feed sources at their terminals for high directivity and relatively low cost. In the third project, an innovative design technique of a dual circularly polarized feed source suitable for a parabolic reflector working in two far-off bands with 1:1.8 ratio is proposed, which can find applications in satellite communications (SATCOM). The proposed design covers an impedance bandwidth of 500 MHz in Ku-band (14.2-14.8 GHz), and 1 GHz in K-band (25-26 GHz), with a peak directivity of almost 15 dBic and axial ratio below 3dB over the entire bandwidth for both bands. This feed source assures that the half-edge-illumination beamwidths are the same for both the bands for an offset parabolic reflector of focal-length-to-diameter (f/d) ratio of 1.5. The feed prototype is built, and simulation results are experimentally validated.