Description and Performance of an L-Band Radiometer with Digital Beamforming

Abstract

This paper presents the description and performance tests of an L-band microwave radiometer with Digital Beamforming (DBF), developed for the Passive Advanced Unit (PAU) for ocean monitoring project. PAU is an instrument that combines, in a single receiver and without time multiplexing, a microwave radiometer at L-band (PAU-RAD) and a GPS-reflectometer (PAU-GNSS-R). This paper focuses on the PAU-RAD beamformer's first results, analyzing the hardware and software required for the developed prototype. Finally, it discusses the first results measured in the Universitat Politè cnica de Catalunya (UPC) anechoic chamber.

An L-Band Phased Array Radiometer for Sea Surface Salinity in Coastal Zones

“…For the L-band phased array radiometer, the main beam efficiency (MBE) and the half-power beamwidth are two key specifications, which have a dependence on the adjacent element spacing and the antenna number of the phased array antenna. However, it is well known that the MBE degrades as the adjacent element spacing increases in a phased array antenna [16]. On the other hand, the half-power beamwidth increases as the adjacent element spacing increases in a phased array antenna [16].…”

“…However, it is well known that the MBE degrades as the adjacent element spacing increases in a phased array antenna [16]. On the other hand, the half-power beamwidth increases as the adjacent element spacing increases in a phased array antenna [16]. Meanwhile, the antenna number of the phased array is limited by the airborne platform, especially for a small UAV.…”

“…Meanwhile, the antenna number of the phased array is limited by the airborne platform, especially for a small UAV. Although a high MBE and a high half-power beamwidth are expected in the L-band phased array radiometer, a compromise is made between the MBE and the half-power beamwidth for the phased array in the L-band radiometer, that have a dependence on the adjacent element spacing and the antenna number [16]. As a result, the designed phased array antenna is synthetized by 4×4 rectangular micro-strip patch antennas with the adjacent element spacing 0.55 λ along the This article has been accepted for publication in a future issue of this journal, but has not been fully edited.…”

“…It employs a single receiver to reduce the complexity of the system. In addition, It can also measure the sea surface TB of the same scene in multiple incidence angles to improve SSS retrieved accuracy [16] [17]. The paper is devoted to the L-band phased array radiometer with a phased array and a single receiver.…”

Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

“…However here we will present a method based on a beam forming technique because it is equally applicable for the active probing data (for which the aperture synthesis method is not straightforward). Usually beam forming is used as a real-time technique to control the direction of the beam launched by the phased array of antennas or received from one or several particular directions [16]. We use the same method in a post processing stage by synthesising a beam and then virtually steering it over viewing angles.…”