Double-Reflector Configuration for Optimal Exposure of Wideband Focal-Plane Arrays With Optical Beamforming

Abstract

. (2017). Double reflector configuration for optimal exposure of wideband focal plane arrays with optical beamforming. IEEE Transactions on Antennas and Propagation, 65(8), 4316-4321. [7935463]. DOI: 10.1109/TAP.2017 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract-An optimized double-reflector antenna concept for a wideband focal plane array (FPA) configuration is presented for Ka-band applications with a limited scan range, e.g. ground terminals for satellite communication. The proposed reflector configuration allows to maximize the number of active array elements and minimize the actual array size during scanning. In addition, the FPA configuration has been optimized for wideband optical true-time-delay (TTD) beamforming, resulting in wideband operation from 20-40 GHz. Based on a minimum required 80 % aperture efficiency at 30 GHz, the double-reflector concept allows expanding the illuminated region of the array by a factor of 60 as compared to traditional prime-focus configurations. The proposed configuration also decreases the magnification factor M by a factor of 2.5, as compared to the double-parabolic configuration for a ±1.5 0 scan range.

Reflector Synthesis for Wide-Scanning Focal Plane Arrays

“…The aperture efficiency estimation includes the radiation efficiency of the reflector, taper efficiency, spill-over efficiency, and polarization efficiency. It is determined according to [17].…”

“…Another possible problem is related to the required linear phase distribution. In [17], it was shown that even at broadside this cannot be realized with a classical prime-focus FPA.…”

“…However, the presented approach in [23] is limited to reflectors with a high magnification factor M = D/D s 1, where D s is the size of the subreflector. At the same time, for double-reflector systems, relatively large subreflectors are required in case of wide-angle scanning [17]. By using an offset configuration as shown in Fig.…”

“…In summary, in this section, we have derived a direct relation between the shape of the reflectors and the total cost function. The shape of the reflectors can be expressed in terms of polynomial coefficients as in (1), (17), and (19) including design features like reflector shape discontinuities and the shifts of the polynomial function along the coordinates axis. The total cost function is presented as a combination of different optimization goals in (16).…”

ARoF-Fed Antenna Architectures for 5G Networks

“…Moreover, the FPA concept also allows the distribution of the transmit power over several array elements and, thus, amplifiers. The reduced peak-power requirement per element results in the possibility to use silicon-based technology, as shown in [3,4], which would reduce the overall cost of the solution.…”