Kevin M. K. H. Leong

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—The analysis of resonant-type antennas based on the fundamental infinite wavelength supported by certain periodic structures is presented. Since the phase shift is zero for a unit-cell that supports an infinite wavelength, the physical size of the antenna can be arbitrary; the antenna's size is independent of the resonance phenomenon. The antenna's(More)
Novel microwave lenses are presented which are realized by interfacing a right-handed (RH) material with a left-handed (LH) material. The conic LH/RH interfaces required to realize LH lenses are presented. A novel parabolic refractor based on the composite right/left-handed (CRLH) metamaterial is also experimentally demonstrated.
—A wireless sensor server is developed based on a reconfigurable active smart-antenna/retrodirective array. The system can serve as both a retrodirective array transponder and a smart-antenna receiver simply by changing the frequency of the local oscillator applied to the mixers, enabling it to best utilize its hardware to suit its communication(More)
—In this paper, the applicability of the power coupler designed based on the infinite wavelength phenomenon present in composite right/left handed transmission lines is investigated. The coupler is used as a power divider at 2.36 GHz. Results show excellent output power balance for two examples of the power divider. One has equally spaced output ports while(More)
This paper will discuss the recent developments by the author's group in the field of RF front-end technology design using the active antenna approach. This will include stand alone RF front-end components such as an integrated polarization selective mixer antenna as well as more functional front-end circuitry such as a retrodirective array transponder.(More)
Planar antennas are often called upon to bridge the gap between the photonics and microwave fields. Design of such antennas requires a culmination of knowledge acquired from the study of both research areas. This paper will discuss our efforts in the design of novel planar antenna structures for microwave-photonics applications, which stress a high level of(More)
I. Introduction When receiving a signal from an unspecified direction, retrodirective arrays [1] are able to transmit a signal response to that same direction without any previous knowledge of the source direction. This function is performed automatically, without the use of phase-shifters or digital circuitry. The capability to perform high gain antenna(More)
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