A Review on the Development of Rotman Lens Antenna

Abstract

Rotman lenses are the beguiling devices used by the beamforming networks (BFNs). These lenses are generally used in the radar surveillance systems to see targets in multiple directions due to its multibeam capability without physically moving the antenna system. Now a days these lenses are being integrated into many radars and electronic warfare systems around the world. The antenna should be capable of producing multiple beams which can be steered without changing the orientation of the antenna. Microwave lenses are the one who support low-phase error, wideband, and wide-angle scanning. They are the true time delay (TTD) devices producing frequency independent beam steering. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size and networks (BFNs). This paper will review and analyze various design concepts used over the years to improve the scanning capability of the lens developed by various researchers.

Multiobjective Optimization of a Rotman Lens through the QLWS Minimization

“…It is remarked that due to the exploitation of the QLWS in (3), the different objectives considered in our synthesis have been reached at different iterations according to the priorities 4 International Journal of Antennas and Propagation that we have set a priori. No one told the algorithm to make a "switch" on what it was searching; such an information is already coded in the QLWS.…”

“…In this regard, it is noted that the design of a Rotman lens involves the achievement of different concurring targets and/or constraints, such as the reduction of the lens insertion losses, the gain losses of the scanned beams, and the lens encumbrance. Accordingly, the optimal calculation of the three unknowns needed for the design of a Rotman lens generally requires solving a multiobjective problem [2][3][4]. However, although many papers have been written [5][6][7][8][9][10][11][12][13] with the aim of improving the lens architecture originally proposed by Rotman, just a few of them focus on the multiobjective nature of the lens synthesis.…”

Flexible-Resolution, Arbitrary-Input, and Tunable Rotman Lens Spectrum Decomposer

“…3) Select a set of parameters ω 0 , N , d, α 0 γ to accommodate the [f min , f max ] according to (11). 4) Determine the RL geometry in terms of its transmission line lengths, left contour and right contour according to (18), (21) and (20), respectively. 5) Determine a number of ports based on the room available and their position on the left contour using (10).…”

Design and Performance Analysis of Millimetre-Wave Rotman Lens-Based Array Beamforming Networks for Large-Scale Antenna Subsystems

“…The theoretical formulations have been modified and improved over the years, based on the rigorous equations derived from the geometrical optics (GO) [24][25][26]. The design of the trifocal lens-based beamformer with the homogeneous medium is controlled by a series of equations that set the focal points, array positions, and lengths of transmission lines, in order to provide the antenna array with the beam patterns that can be effectively steered in certain directions, along with suppressing the undesired ones [27][28][29]. The RL design and synthesis procedure ensures the parameters to be tuned to effectively optimise the network performance, in terms of phase and amplitude errors, reflection and transmission coefficients, and sidelobe levels (SLLs) [30][31][32].…”