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Dong J.,Microwave Engineering Corporation MEC | Zaghloul A.I.,Virginia Polytechnic Institute and State University | Zaghloul A.I.,U.S. Army
IEEE Transactions on Antennas and Propagation | Year: 2011

Microwave lenses such as the Bootlace/Rotman lenses are designed by placing physical ports of lens input on the theoretical phase centers. These phase center positions are calculated using geometrical optic method under the assumptions of perfect cylindrical waves and true time delay. A real physical lens does not satisfy these conditions due to different port implementation approaches and mutual coupling effects. Full wave investigations and measurements have indicated strong variation at both phase and amplitude couplings between the input and output ports. Efficient theoretical models predicting both phase and amplitude performances are still in great demand to perform advanced lens optimization. The full wave simulation demonstrates accurate results. However, it is not convenient in optimization iterations due to its high computational cost and sophisticated programming process. Based on a ray tracing concept recently explored by the authors, this paper extends its design and formulate a suitable approach for general lens simulation. A microwave lens is systematically treated by hybrid of a flexible tapered port model and multiple-ray-path coupling approach. This method leads to designing the minimum return loss tapered port and fast lens simulation of reasonable accuracy. The predicted results of amplitude, phase couplings, array factors are validated by both full wave simulation and measurement. The comparison shows that the proposed method is fast, accurate and sufficient to predict various microwave lens parameters. This concept can be extended to designing stripline and waveguide lenses as well. © 2011 IEEE. Source

Dong J.,Virginia Polytechnic Institute and State University | Dong J.,Microwave Engineering Corporation MEC | Zaghloul A.I.,Virginia Polytechnic Institute and State University | Zaghloul A.I.,U.S. Army
IET Microwaves, Antennas and Propagation | Year: 2010

A low-profile, high-performance beam steerable antenna, also referred to as electrically steerable array or array, system is proposed for vehicular sensor applications. The antenna aperture is realised by a phased array fed with a tri-focal Rotman lens. Theory of designing the beam-forming network and an improved parametric study are presented, while the narrow-H-plane, broad-E-plane microstrip antenna fed by the printed lens is investigated for extremely high-frequency -band operation. The full wave simulation demonstrates good results for the antenna use over the required two-dimensional scanning range of ±45°. © 2010 The Institution of Engineering and Technology. Source

Dong J.,Microwave Engineering Corporation MEC | Cheung R.,Microwave Engineering Corporation MEC
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2011

Rotman lens is well-known passive device for its broadband feature in terms of the true time delay and low dispersive properties. However, the broad bandwidth preserving optimal amplitude/phase performance does not come naturally in a system level design. In this paper, the presented printed lens has considered extensive parameters while performing a full wave structure evolution. Design concepts and important electrical parameters are studied in both FEKO and HFSS. While we focuses on the numerical synthesis of the lens, typical measurement of return loss is presented as well. The resulting lens has a 98 input-to-output configuration, operating from 28 GHz with outstanding phase/amplitude stability and scanning capability. © 2011 IEEE. Source

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