Taylor Amplitude Distribution Research Articles

Design of a Compact Omnidirectional Leaky-Wave Antenna Fed by Higher Order Mode

This article presents a novel leaky-wave antenna (LWA) based on a dielectric-filled rectangular waveguide (RWG) and fed by a higher order mode. The proposed quasi-uniform LWA has a compact configuration that is suitable for microwave applications, featuring the omnidirectional radiation patterns and low cross-polarization. In the frequency band of interest, the higher order mode, i.e., the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode, performs as a fast wave in the proposed quasi-uniform LWA, radiating via the transverse slots etched on the walls. The advantage of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode for LWA applications is analyzed and demonstrated. This higher order mode is excited via a mode convertor from an inline coaxial line to the dielectric-filled RWG. For the reduction in sidelobe levels at high frequencies, −25 dB Taylor amplitude distribution is applied to the etched slots. The dielectric-filled LWA with the inline coaxial feeding is fabricated and measured. The measurement is consistent with the simulation, showing frequency-driven beam-scanning capability with low cross-polarization in the elevation plane. The simulated and measured radiation patterns in the azimuth plane illustrate the omnidirectional radiation patterns and thus confirm the radiating performance of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode in the proposed LWA. The advantages of the scanned beams and omnidirectional radiations are promising for radar systems.

Light-weight wideband antenna array with low sidelobes for SAR applications

PurposeThe purpose of this study is to achieve the low-cost, light-weight and compact antenna array with wide bandwidth and low side lobe levels for synthetic aperture radar (SAR) applications in Ku frequency band.Design/methodology/approachA compact design of a rectangular microstrip patch antenna array using multilayered dielectric structure is presented in Ku-band for advanced broadband SAR systems. In this design, stepped pins are used to connect the microstrip feed lines to the radiating patches.FindingsThe simulation and fabrication results of the multilayered antenna and a 1×16-element linear array of the antenna with Taylor amplitude distribution in the feeding network are presented. The antenna element has a 10-dB impedance bandwidth of more than 26%, and the linear array shows reduction in bandwidth percentage (about 15.4%). Thanks to Taylor amplitude tapering, the side lobe level (SLL) of the array is lower than −24 dB. The maximum measured gains of the antenna element and the linear array are 7 and 19.2 dBi at the center frequency, respectively.Originality/valueIn the communication systems, a high gain narrow beamwidth radiation pattern achieved by an array of multiple antenna elements with optimized spacing is a solution to overcome the path loss, atmospheric loss, polarization loss, etc. Also, wideband characteristics and compact size are desirable in satellite and SAR systems. This paper provides the combination of these features by microstrip structures.

Wideband stacked patch antenna array with reduced sidelobes for Ku-band applications

ABSTRACT The most important features of microstrip antenna are low cost, low profile, and light weight. But the patch antenna usually has narrow bandwidth. In this paper, for overcoming the mentioned problem, a new approach to obtain a wider bandwidth is proposed. For this purpose, stacked patch above the main patch is used. The design and fabrication method of the proposed antenna is described carefully. Then, a compact microstrip fed line linear array antenna with Taylor amplitude distribution in the feeding network is designed. The measured results show the 10-dB impedance bandwidth of about 23% for the single element and 20% for the linear array. Moreover, the measured side lobe level (SLL) of the array is lower than −21 dB. The results for the simulations and experiments are in a good agreement.

Transversely Slotted SIW Leaky-Wave Antenna Featuring Rapid Beam-Scanning for Millimeter-Wave Applications

Loading effects of radiating discontinuities have been explored to increase the phase constant’ frequency sensitivity of leaky-wave antennas (LWAs), based on which a quasi-uniform transversely slotted substrate integrated waveguide LWA featuring rapid beam-scanning and its hexagonal array have been proposed and investigated for millimeter-wave applications. The design concept is simply based on the use of a short period of unit cells and a long transverse slot with a sharp inductive reactance, and it has been theoretically elaborated and effectively validated by both full-wave and circuit-based simulations. A taper design with −25 dB Taylor amplitude distribution is implemented for the proposed LWA to have a low sidelobe radiation. For practical system applications, a hexagonal array consisting of six proposed LWAs is developed to provide an omnidirectional coverage in the azimuth plane while remaining the rapid frequency-driven beam-scanning in the elevation plane. Both the measured and simulated results are in an acceptable agreement with respect to the LWA block and the associated hexagonal array in terms of circuit and radiation performances. The proposed antenna will be a good candidate to be applied for prospective millimeter-wave systems such as autonomous driving and flying.

Design of microstrip-fed series array of dielectricresonator antennas

An experimental procedure for designing a microstrip-fed series array of dielectric resonator antennas is presented. The procedure was used to design a 10 element array with a Taylor amplitude distribution. A gain of 13.2 dBi was measured at 8.2 GHz with maximum sidelobe levels of –17.5 dB. The cross-polarisation levels were also measured to be quite low, at ~20 dB below the peak.