Pattern reconfigurable techniques for LP and CP antennas with the broadside and conical beams

© Institution of Engineering and Technology.All Rights Reserved. This paper presents two pattern reconfigurable techniques to realize linear (LP) and circular (CP) broadside and conical-beam switchable radiation patterns from a single antenna. First, a wideband monopolar patch and a L-probe fed patch were organically integrated together to achieve a wideband (2.25 to 2.85 GHz) broadside and conical-beam pattern reconfigurable system that radiates LP radiation. Radiation coverage and wireless channel capacity were improved significantly making the reported LP antenna a good candidate as a ceiling mounted antenna for indoor wireless communications. On the other hand, a circularly-polarized (CP) broadside and conical-beam reconfigurable antenna would be preferred for satellite communications. To realize it, we successfully excited both the TM11 and TM21 modes on a circular patch with an annular slot antenna. A reconfigurable feeding network was designed to provide the correct excitations for these two modes. CP switchable broadside and conical radiated beams were realized within the same overlapping frequency ranges from 2.45 to 2.65 GHz. Both the LP and CP antennas were fabricated and tested. Experimental results show good agreement with their simulated performance characteristics. Very good radiation performance was obtained

Compact, omni-directional, circularly-polarized mm-Wave antenna for device-to-device (D2D) communications in future 5G cellular systems

© 2017 IEEE. A simple, compact, omni-directional, circularly-polarized (CP) millimeter-wave antenna for Device-to-Device (D2D) communications in the next generation (5G) cellular systems is reported. It is a CP omni-directional antenna operating at 28 GHz for mobile terminals. The antenna combines a vertical electric monopole element with four magnetic elements to coherently excite parallel electric and magnetic dipoles. This combination generates the omni-directional CP radiation. The overlapping -10-dB impedance and 3-dB axial ratio (AR) bandwidth is from 27 to 28.5 GHz, which covers the 28 GHz frequency band proposed for 5G mobile cellular networks (i.e., from 27.5 to 28.35 GHz). The antenna has an omni-directional radiation pattern at 28 GHz whose peak realized RHCP gain is 2.08 dBic and whose 3-dB AR beamwidth is wide, from elevation angles 3° to 136°. Mass production of the antenna is possible by PCB manufacturing technologies. The overall size is 3.44 mm × 3.44 mm × 1 mm (ka = 1.1017). Consequently, it could be embedded in many current popular, smart wireless devices such as cell phones, laptops, digital watches, and smart glasses as well as their future versions for operation in 5G cellular networks

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium