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291 results on '"Luk, K. M."'

4. A monopolar patch antenna with very wide impedance bandwidth

Author

Lau, K.-L., Li, P., and Luk, K.-M.

Subjects
Antennas (Electronics) -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

A monopolar patch antenna that utilizes a bandwidth broadening technique is investigated experimentally and numerically. The proposed antenna consists of a monopole that is formed by connecting four trapezoidal plates orthogonally. A circular patch, which is shorted to the circular ground plane by four shorting wires, is placed at the top of the monopole. The antenna possesses 10-and 14-dB return loss bandwidths of 138% and 107.2% respectively, which is about 49 times that of the corresponding monopolar wire-patch antenna. Also, it provides monopole-like radiation patterns over such wide operating bandwidth. As the proposed antenna can achieve such wide impedance bandwidth with relatively low profile, it is very suitable for multi-band mobile communication systems. Index Terms--Monopolar patch antenna.

Published
2005

7. FDTD Analysis of U-Slot Rectangular Patch Antenna

Author

Luk, K. M, Tong, K. F, Shum, S. M, Lee, K. F, and Lee, R. Q

Subjects
Electronics And Electrical Engineering
Abstract

The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

Published
1997
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9. Input Impedance of the Slot-Fed Dielectric Resonator Antenna with/without a Backing Cavity

Author

Chow, K. Y., Leung, K. W., Luk, K. M., and Yung, Edward K. N.

Subjects
Cavity resonators -- Testing, Dielectric resonators -- Testing, Antennas (Electronics) -- Testing, Business, Computers, Electronics, Electronics and electrical industries
Abstract

The slot-fed dielectric resonator antennas with or without a backing cavity are studied theoretically and experimentally. A coaxial cable is used to excite the slot. The input impedances and return losses of the antennas are found and discussed. Index Terms--Cavity resonators, dielectric antennas, mode-matching methods, method of moment (MoM).

Published
2001

10. Experimental Study of a Microstrip Patch Antenna with an L-Shaped Probe

Author

Mak, C. L., Luk, K. M., Lee, K. F., and Chow, Y. L.

Subjects
Bandwidth -- Research, Antennas (Electronics) -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

The L-shaped probe is shown to be an attractive feed for the thick microstrip antenna (thickness around 10% of the operating wavelength). A parametric study on the rectangular patch antenna is presented. It is found that the antenna attains 36% impedance bandwidth (SWR [is less than or equal to] 2) as well as gain bandwidth and about 7-dBi average gain. A two-element array fed by L-probes is also proposed. Experiments show that the array design can substantially suppress the cross polarization of the proposed antenna. Both the antennas have stable radiation patterns across the passband. Moreover, the measured resonant frequencies of the proposed antenna agree well with an existing formula and the L-probe does not have much effect on the resonant frequency. Index Terms--Bandwidth widening, microstrip patch antennas.

Published
2000

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