Conformal phased array with beam forming for airborne satellite communication

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed

A Wideband Base Station Antenna Element with Stable Radiation Pattern and Reduced Beam Squint

© 2017 IEEE. This paper presents the design procedure, optimization strategy, theoretical analysis, and experimental results of a wideband dual-polarized base station antenna element with superior performance. The proposed antenna element consists of four electric folded dipoles arranged in an octagon shape that are excited simultaneously for each polarization. It provides ±45° slant-polarized radiation that meets all the requirements for base station antenna elements, including stable radiation patterns, low cross polarization level, high port-to-port isolation, and excellent matching across the wide band. The problem of beam squint for beam-tilted arrays is discussed and it is found that the geometry of this element serves to reduce beam squint. Experimental results show that this element has a wide bandwidth of 46.4% from 1.69 to 2.71 GHz with ≥15-dB return loss and 9.8 ± 0.9-dBi gain. Across this wide band, the variations of the half-power-beamwidths of the two polarizations are all within 66.5° ± 5.5°, the port-to-port isolation is >28 dB, the cross-polarization discrimination is >25 dB, and most importantly, the beam squint is <4° with a maximum 10° down-tilt

Wideband Differentially-Fed Slot Antenna and Array With Circularly Polarized Radiation for Millimeter-Wave Applications

© 2022 IEEE - All rights reserved. This is the accepted manuscript version of the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2022.3145481A wideband differentially-fed slot antenna is presented for millimeter-wave (mmWave) applications. A novel method of using stepped corner-shaped slot is first utilized to establish the wideband circularly polarized (CP) radiation. In the configuration of corner-shaped slot, two wide open slots at the ends are utilized for effective orthogonal radiation, while the narrow slot at the center is utilized for power transmission and quadrature phase delay. An equivalent circuit is given to illustrate the inner working principle for CP radiation. In addition, square cuts are etched on the four corners of the radiating patches to further increase the axial ratio (AR) and impedance bandwidth. Based on this design concept, the antenna element was first designed and fabricated for performance verification. Then, a 1×4 linear array with beam scanning performance and a 4×4 planar array with high gain and stable radiation were designed and fabricated. Both the simulated and measured results show that the 1×4 linear array and 4×4 planar array can have wide overlapped impedance and AR bandwidths of 30.6% and 33.6% with thickness of 0.16λ0. The advantages of compact size and wide bandwidth make the presented antenna a good candidate for mmWave applications.Peer reviewedFinal Accepted Versio

The Study of Reconfigurable Antennas and Associated Circuitry

This research focuses on the design of pattern reconfigurable antennas and the associated circuitry. The proposed pattern reconfigurable antenna designs benefit from advantages such as maximum pattern diversity and optimum switching circuits to realise 5G reconfigurable antennas. Whereas MIMO based solutions can provide increased channel capacity, they demand high computational capability and power consumption due to multiple channel processing. This prevents their use in many applications most notably in the Internet of Things where power consumption is of key importance. A switched-beam diversity allows an energy-efficient solution improving the link budget even for small low-cost battery operated IoT/sensor network applications. The main focus of the antenna reconfiguration in this work is for switched-beam diversity. The fundamental switching elements are discussed including basic PIN diode circuits. Techniques to switch the antenna element in the feed or shorting the antenna element to the ground plane are presented. A back-to-back microstrip patch antenna with two hemispherical switchable patterns is proposed. The patch elements on a common ground plane, are switched with a single-pole double-throw PIN diode circuit. Switching the feed selects either of two identical oppositely oriented radiation patterns for maximum diversity in one plane. The identical design of the antenna elements provides similar performance control of frequency and radiation pattern in different states. This antenna provides a simple solution to cross-layer PIN diode circuit designs. A mirrored structure study provides an understanding of performance control for different switching states. A printed inverted-F antenna is presented for monopole reconfigurable antenna design. The proposed low-profile antenna consists of one main radiator and one parasitic element. By shorting the parasitic element to the ground plane using only one PIN diode, the antenna is capable of switching both the pattern and polarisation across the full bandwidth. The switched orthogonal pattern provides the maximum spatial pattern diversity and is realised using a simple structure. Then, a dual-stub coplanar Vivaldi antenna with a parasitic element is presented for the 5G mm-Wave band. The use of a dual-stub coupled between the parasitic element and two tapered slots is researched. The parasitic element shape and size is optimised to increase the realised gain. A bandpass coupled line filter is used for frequency selective features. The use of slits on the outer edge of the ground plane provides a greater maximum gain. This integrated filtenna offers lower insertion loss than the commercial DC blocks. The UWB antenna with an integrated filter can be used for harmonic suppression. The influence of the integrated filter circuit close to the antenna geometry informs the design of PIN diode circuit switching and power supply in the 5G band. Based on the filter design in the mm-Wave band, a method of designing a feasible DC power supply for the PIN diode in the mm-Wave band is studied. A printed Yagi-Uda antenna array is integrated with switching circuitry to realise a switched 180° hemispheres radiation pattern. The antenna realises a maximum diversity in one plane. The study offers the possibility to use PIN diodes in the mm-Wave band for reconfigurable antenna designs. For the presented antennas, key geometric parameters are discussed for improved understanding of the trade-offs in radiation pattern/beamwidth and gain control for reconfigurable antenna applications