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)
In this paper, progress toward developing solid-state power-amplifier modules at 0.65 THz is reported. This work is enabled by a &gt;;1 THz f<sub>MAX</sub> InP HEMT transistor with a 30-nm gate and an integrated circuit process specifically tailored for circuits operating at frequencies approaching 1 THz. The building block of the reported amplifier modules(More)
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 environment.(More)
In this paper, a 210 GHz solid-state power amplifier (SSPA) module is presented. The amplifier MMIC uses sub-50 nm InP HEMT transistors, coplanar waveguide (CPW) technology, and on-chip electromagnetic transitions to waveguide. Two levels of power combining were used on-chip to achieve total transistor output periphery of 0.96 mm. The first level is a 1:4(More)
In this paper, we demonstrate that the cascode amplifier topology can be extended to operating frequencies &#62; 500 GHz. Two packaged cascode amplifiers are reported, including a broadband 3 stage amplifier with &#126;17 dB gain and 8.3 dB packaged noise figure at 300 GHz and a narrowband amplifier with 10 dB gain at 0.55 THz measured in package. Both of(More)
In the paper, we report on recent progress in scaling InP HEMT MMIC technology to Submillimeter (SMMW) and Terahertz (THz) frequencies. We show that amplification has reached 0.85 THz, with low noise and power amplification in packaged amplifiers at this frequency. Moreover, we show that the entire receiver and exciter function, including mixing and(More)
In this paper, we demonstrate a packaged sub-millimeter wave solid-state power amplifier (SSPA). The SSPA is implemented in coplanar waveguide (CPW) and uses an advanced high <i>f</i><sub>MAX</sub> InP HEMT transistor with a sub 50-nm gate. A monolithically integrated CPW dipole-to-waveguide transition eliminates the need for wirebonding and additional(More)
This paper describes the development of silicon micromachined waveguide structures operating in the WR1.5 waveguide band (500-750 GHz). Average waveguide loss of 0.15 dB/mm was measured at 600 GHz. Capabilities of the proposed approach have been shown with the development of a 570-GHz three-pole waveguide bandpass filter that has a 0.9-dB passband loss and(More)
Metamaterials (MMs) with simultaneous negative values of permittivity (ε) and permeability (μ), known as LH materials (LHMs) [1], have lead to the development of novel microwave applications, concepts, and devices [2]. Electromagnetic waves traveling in a LHM experience reversal of the Doppler effect, the Cerenkov effect, and Snell’s law. The latter(More)