L-Band Antenna Array for Next Generation DLR Airborne SAR Sensor

Lorente, Diego; Limbach, Markus; Gabler, Bernd

doi:10.23919/gemic.2019.8698151

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…At present, to solve the problems of terrain mapping, air and space reconnaissance, and missile weapons control, Radar Systems (RS) based on aerospace vehicles are actively used [1,2]. An important feature of such advanced systems is the use of underwing, under-fuselage and other types of Antenna Arrays (AA), as well as appropriate space-time signal processing [3,4]. However, the operation algorithms of many existing RS provide for the processing of narrowband signals only.…”

Section: Introductionmentioning

confidence: 99%

Practical imaging algorithms in ultra-wideband radar systems using active aperture synthesis and stochastic probing signals

Zhyla¹,

Volosyuk²,

Павликов³

et al. 2023

reks

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The subject of the manuscript is the algorithms for radar imaging. This research develops imaging methods and algorithms for wideband and ultrawideband active aperture synthesis systems with antenna arrays and stochastic probing signals. The use of antenna arrays makes it possible to obtain radar images without the need to move radar or antenna system in space. The use of wideband and ultra-wideband stochastic probing signals is justified by their narrow autocorrelation functions. This increased the resolution of the obtained images. The main idea of the proposed algorithms is to filter the original wideband signal into several narrowband processes. Furthermore, only the central frequencies of each narrowband signal were processed. This approach allows us to use the classical widespread methods of aperture synthesis for the case of a wideband signal. Usually, they are applicable only for narrowband signals that satisfy the condition of a quasi-monochromatic approximation. This significantly reduces the overall computational complexity of the imaging algorithm, which simplifies its further practical implementation on the existing radioelement base. Because of the simulation, a primary radar image has been obtained and the overall performance of the proposed approach to processing wideband signals has been confirmed. An increase in the quality of the obtained image when using a multiple of frequency ranges is shown. An experimental study of the effect of processing a wideband signal only at its centre frequency instead of the entire frequency band is conducted. During the experiment, the correlation functions of the signals received by two spaced receivers were obtained. As a result, the Van Cittert-Zernike theorem has been experimentally confirmed. It allows signal processing only at its centre frequency instead of the entire frequency band. Simultaneously, the prospect of expanding the bandwidth of the probing signal is indicated. It, in the presence of a wideband element base and devices for high-speed signal processing, will further increase the imaging resolution of a radar system.

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Section: Introductionmentioning

confidence: 99%

Practical imaging algorithms in ultra-wideband radar systems using active aperture synthesis and stochastic probing signals

Zhyla¹,

Volosyuk²,

Павликов³

et al. 2023

reks

View full text Add to dashboard Cite

show abstract

“…Especially advantageous are the applications of SAR for lower frequencies [5,6] such as P-Band (216-450 MHz) or L-Band (1-2 GHz) [7]. Due to the penetrating nature of electromagnetic waves at higher wavelengths and by means of interferometry, SAR becomes an interesting way to monitor forest density and estimate forest height by using tomography [8], as well as to perform geology and glaciology studies for the measurement of snow, ice layer thicknesses and soil moisture.…”

Section: Introductionmentioning

confidence: 99%

“…The spacing between the antenna elements is chosen to be 0.6λ, calculated at the center frequency of operation f 0 . Due to its compact implementation, an inter-element spacing of up to 0.48λ can be also considered if a higher degree of integration is desired [6]. However, for this work, a greater distance between antenna elements has to be used due to mechanical reasons, since the geometrical 90°rotation of the elements limits the access of the antenna feeding connectors.…”

mentioning

confidence: 99%

Sequential 90° Rotation of Dual-Polarized Antenna Elements in Linear Phased Arrays with Improved Cross-Polarization Level for Airborne Synthetic Aperture Radar Applications

et al. 2021

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In this work, a novel rotation approach for the antenna elements of a linear phased array is presented. The proposed method improves by up to 14 dB the cross-polarization level within the main beam by performing a sequential 90° rotation of the identical array elements, and achieving measured cross-polarization suppressions of 40 dB. This configuration is validated by means of simulation and measurements of a manufactured linear array of five dual-polarized cavity-box aperture coupled stacked patch antennas operating in L-Band, and considering both uniform amplitude and phase distribution and beamforming with amplitude tapering. The analysis is further extended by applying and comparing the proposed design with the 180° rotation and non-rotation topologies. This technique is expected to be used for the next generation L-Band Airborne Synthetic Aperture Radar Sensor of the German Aerospace Center (DLR).

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“…A new dual linear polarized L-band phased array antenna is currently under development at the Microwaves and Radar Institute of the German Aerospace Center (DLR). It will be part of the next generation airborne SAR sensor F-SAR [1]. The beam is tilted 40° off nadir, while the antenna is mounted flat to one side of the fuselage.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Phased Array with Planar Near-Field Techniques Based on Far-Field Measurements of a Sub-Array in a CATR

Gabler

Lorente

Coevering³

2021

2021 Antenna Measurement Techniques Association Symposium (AMTA)

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Phased array antennas are often built from sub-arrays with identical or symmetrical layout. At an early project stage, performance verification measurements of the sub-array are valuable to proof the single module design. However, the characteristics of the final antenna are questionable without further processing. This work presents a concept that is based on far-field measurements of a sub-array in a Compact Antenna Test Range (CATR) in conjunction with planar near-field (PNF) processing to synthesize the entire phased array antenna characteristics. The procedure is explained with an example of a dual linear polarized L-band planar phased array antenna for an airborne synthetic aperture radar application. It is shown that the measured sub-array can be complemented by the synthesized twin to evaluate the characteristics of a final antenna that is not yet available in this form. The resulting performance of the synthesized entire phased array is presented and compared with simulations. The presented post-processing method would be beneficial to characterizing radiation patterns of large phased arrays by measuring only sub-arrays in a limited test-zone with any measurement principle.

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L-Band Antenna Array for Next Generation DLR Airborne SAR Sensor

Cited by 5 publications

References 6 publications

Practical imaging algorithms in ultra-wideband radar systems using active aperture synthesis and stochastic probing signals

Practical imaging algorithms in ultra-wideband radar systems using active aperture synthesis and stochastic probing signals

Sequential 90° Rotation of Dual-Polarized Antenna Elements in Linear Phased Arrays with Improved Cross-Polarization Level for Airborne Synthetic Aperture Radar Applications

Synthesis of a Phased Array with Planar Near-Field Techniques Based on Far-Field Measurements of a Sub-Array in a CATR

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