A wideband spatial beamformer employing a rectangular array of planar monopoles

Micro & Optical Tech Letters

Attakitmongkol

Bunsanit

et al. 2010

Recently, an outstanding wideband beamformer utilizing only space domain, not time or frequency domain, has been proposed, so-called wideband spatial beamformer. The advantage of this beamformer is that it requires only attenuators or amplifiers to perform beam formation in wide frequency band as its weighting coefficients become real values. As a result, tapped delay lines, frequency filters, or phase shifters are avoidable. This article presents an extension work for the mentioned wideband spatial beamformer. The beamforming algorithm is modified to produce multibeam patterns with one set of real-valued weights for the purpose of energy saving. The proposed concept is tested through simulated and measured results to confirm beamforming capability.

Section: Introductionmentioning

confidence: 98%

“…In addition, the response of filters has to be sharp enough so that the overlapping of frequency in each sub-band does not exist. For the last category, involving only space domain has been recently proposed, namely fully spatial beamformer [4]. The work presented in Ref.…”

Section: Introductionmentioning

confidence: 99%

Wideband multibeam formation using fully spatial signal processing for indoor communications

Micro & Optical Tech Letters

Attakitmongkol

Bunsanit

et al. 2010

“…An interesting example of a wideband spatial beamformer was described in [4], and its practical implementation was demonstrated in [5]. The operation of this beamformer relies on the use of a 2D array antenna consisting of identical wideband-antenna elements arranged in a horizontal rectangular lattice with spacing equal to a half-wavelength at the highest frequency of operation.…”

Section: Introductionmentioning

confidence: 99%

“…In the methods described in [4,5], the weights are calculated by disregarding the mutual-coupling effects between the array elements. However, as the mutual-coupling effect is present in the actual array, the resulting radiation pattern features an increased side-lobe level.…”

Section: Introductionmentioning

confidence: 99%

A wideband array antenna with beam‐steering capability using real valued weights

Bialkowski

Micro & Optical Tech Letters

2005

This article presents an array antenna with beam‐steering capability in azimuth over a wide frequency band using real‐valued weighting coefficients that can be realized in practice by amplifiers or attenuators. The described beamforming scheme relies on a 2D (instead of 1D) array structure in order to make sure that there are enough degrees of freedom to realize a given radiation pattern in both the angular and frequency domains. In the presented approach, weights are determined using an inverse discrete Fourier transform (IDFT) technique by neglecting the mutual coupling between array elements. Because of the presence of mutual coupling, the actual array produces a radiation pattern with increased side‐lobe levels. In order to counter this effect, the design aims to realize the initial radiation pattern with a lower side‐lobe level. This strategy is demonstrated in the design example of 4 × 4 element array. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 287–291, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21329

“…The H(u 1 , u 2 ) is the form of Sinc function to obtain maximum gain in the desired direction [16] which can be given as…”

Section: Fully Spatial Beamformermentioning

confidence: 99%

Refinement Method for Weighting Scheme of Fully Spatial Beamformer

Bunsanit

International Journal of Antennas and Propagation

2012

So far, a wideband spatial beamformer has been proposed. This kind of beamformer has a major contribution as its weighting coefficients are real valued in which they can be simply realized by attenuators or amplifiers. However, so far, the range of attenuation or amplification is relatively large which is not practical for hardware realization. Therefore, this paper proposes a concept to reduce the range of weighting coefficients hence, the hardware realization becomes practical. In this paper, a full prototype of wideband spatial beamformer is constructed to reflect the true beamforming performance of the proposed refinement method. Its radiation patterns obtained from simulation and measurement are compared. As a result, we can reduce the attenuation or amplification range while some radiation characteristic is remained.