A Polarization Reconfigurable Low-Profile Ultrawideband VHF/UHF Airborne Array for Fine-Resolution Sounding of Polar Ice Sheets

Abstract

A polarization-reconfigurable low-profile ultrawideband VHF/UHF antenna array is presented in this paper. The design is based on resistively loaded planar dipole antenna elements backed with a ground plane. The antenna array has two mechanically field-switchable polarization configurations which are designed to measure the crystal orientation of ice sheets. The nominal operating mode of the array is in the vertically polarized configuration with operating frequency ranges from 150 to 550 MHz. The planar dimension of the array is 3.6 m × 0.8 m with a ground plane height of 16 cm (0.08λ low , flow = 150 MHz). Anechoic chamber measurements show that the array performance is in very good agreement with simulated results, for both VSWR and array radiation pattern. It is also shown that the array is capable of handling 1-kW peak power per transmit channel. The antenna array is housed within a flight-qualified composite S2-glass/epoxy fairing and can readily be mounted on airborne platforms, such as Basler BT-67 and Twin Otter, for radar sounding of polar ice sheets and glaciers.

Low Cross-Polarization Vivaldi Arrays

“…This work develops a new class of low cross-polarization, ultra-wideband (UWB) electronically scanned arrays (ESA) to meet the needs of modern multifunctional RF systems [1], high-throughput or low-power communication systems [2][3][4], high resolution radars and sensing imagers [5][6][7][8], polarimeters and radio telescopes [9][10][11], and electronic warfare systems [12][13][14]. Although a number of accomplished UWB-ESAs have been proposed over the past decades [15][16][17][18][19][20][21][22][23] Most high-efficiency (low-loss) UWB-ESA apertures, certainly those that archive BWRs wider than 6:1 such as the Vivaldi array [24], are subject to an inherent bandwidth versus cross-polarization trade-off.…”

“…(1.23)) and thus the ability to correct the receiver system cross-polarization. As discussed in Section 1.2, IXR is a measure of the resulting polarimeter calibratability, and is directly related to the degree of orthogonality between the dual-polarized channels 5 . As a result, low antenna array CPR is an extremely important factor to ensure good IXR (and high channel orthogonality) for high measurement accuracy.…”

“…A dual-polarized 9:1 Vivaldi array was recently used for full polarimetric airborne measurements of snow-over-sea-ice [6]. 5 It is noteworthy to point out that IXR is invariant to the incident polarization coordinate system and the calibration procedure by nature of its definition, unlike typical cross-polarization FoMs used in dual-polarized communication systems that will inevitably change due to such factors like CPR, XPD, XPI, etc. …”

Multi-channel ultra-wideband radar sounder and imager

“…The polarization of each antenna element can be individually reconfigured depending on the target of interest. Details on the antenna array design as well as laboratory measurements of the array performance can be found in [3].…”

Frequency reconfigurable antenna for VHF/UHF digital TV reception on portable devices using switching matching networks

“…Antenna polarization, pattern, and frequency can be adjusted to meet application needs. Principle antenna tuning mechanisms include diodes, varactors, RF switches, and MEMS switches . To cope with diversified band allocations of modern wireless standards, numerous frequency reconfigurable designs are devised for handsets .…”