Showing papers by "Paul R. Young published in 2017"

Wideband Loop Antenna With Electronically Switchable Circular Polarization

Abstract: This letter presents a novel printed antenna with wide bandwidth, high gain, and reconfigurable circular polarizations. A loop antenna is printed on both sides of a dielectric substrate: A dual-p-i-n-diode loaded loop is printed on one side, while a dual-gap loaded smaller loop is printed on the other side. By controlling the on–off states of the p-i-n diodes, the polarization of the proposed antenna can be switched electronically to right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP) over a wideband frequency range. A prototype is fabricated and measured to verify the performance of the antenna. The measured results indicate that the antenna achieves an impedance bandwidth of over 30%, and a 3-dB axial-ratio (AR) bandwidth of 12.7% and 14.9% for RHCP and LHCP, respectively. The measured gain is around 8 dBic for the LHCP state and 7 dBic for the RHCP state. Due to the advantages of wide overlapped bandwidth, simple feeding structure, and high gain, this antenna is promising for applications in dual-CP wireless communication systems.

Inverted-S Antenna With Wideband Circular Polarization and Wide Axial Ratio Beamwidth

Abstract: A novel broadband circularly polarized (CP) antenna with wide axial ratio (AR) beamwidth is proposed. It is composed of two curved arms shaped like an inverted “S.” The mechanisms of wideband CP operation and wide AR beamwidth are explained. To validate the concept, a prototype at C-band is manufactured and measured. Experimental results confirm that the antenna achieves an impedance bandwidth of 63% and a CP bandwidth of 42%. Furthermore, maximum AR beamwidth of 140° is achieved and wide AR beamwidth can be maintained in a frequency bandwidth of 35% in nearly all elevation planes. In addition, the antenna has the advantage of being easily extended to arrays. A four-element array using the proposed antenna is investigated through both simulations and experiments, and achieves 60% CP bandwidth and wide AR beamwidth. The proposed inverted-S antenna can realize wide CP bandwidth and wide AR beamwidth, and can easily form wideband CP arrays.

A novel 5 GHz high gain dual substrate integrated waveguide epsilon near zero antenna for WLAN applications

Abstract: The aim of this work is to enhance the radiation and gain of a microwave antenna by using an Epsilon Near Zero material in the form of a microwave waveguide. High gain dual substrate integrated waveguide epsilon near zero antenna is fabricated for operating at 5 GHz the measurement results are compared with the simulation studies.

Novel theoretical analyses of transverse resonance technique on loaded impedance waveguide

Abstract: A novel theoretical analysis of transmission characteristics of waveguide systems by using transverse resonance technique (TRT) is presented. The purpose of this study is to acquire a method which could simply analyze the propagation parameters of the slotted waveguide which is loaded with discrete impedance. The mathematical model is based on the equivalent transverse resonance circuit, in order to define the propagation condition, the fast/slow modes and losses in the fundamental mode. The result shows that the slotted waveguide will lose the fundamental mode if the loaded capacitive impedance is higher than 77pF/m. The different phase constant pattern of slow mode causes the fundamental mode to converge to the unusual direction and the loss increases rapidly. This novel technique has the advantage of simplicity and compares well with results of electromagnetic simulation and measurement.