Yuan-Tung Cheng

Resonance in a superstrate-loaded cylindrical-rectangular microstrip structure

The complex resonant frequencies of the cylindrical-rectangular microstrip structure loaded with a dielectric superstrate layer is studied using a rigorous full-wave analysis, and the numerical results are obtained using the Galerkin moment method calculation. The numerical convergence for the selected sinusoidal basis functions with and without the edge singularity condition is also discussed. Numerical results for the dependence of the real and imaginary parts of the complex resonant frequencies on the superstrate permittivity and thickness are calculated and analyzed, and are compared with those obtained for the planar microstrip structure. >

Analysis of a cylindrical-rectangular microstrip structure with an airgap

The resonance problem of the cylindrical-rectangular microstrip structure with an airgap between the substrate layer and the ground conducting cylinder is studied by using a rigorous full-wave approach and a moment method calculation. The resonance condition is satisfied by complex resonant frequencies, which provide the information of resonant frequency and half-power bandwidth of the structure. Numerical results indicate that, with the increasing of the airgap thickness, the half-power bandwidth of the structure at the efficient radiating mode of HE/sub 0.1/ is considerably increased, which improves the narrow bandwidth characteristics of microstrip structures. Details of the numerical results, including the results for the planar rectangular microstrip structure with an airgap, are presented and analyzed. >

Printed inverted-F antennas for applications in wireless communication

Introduction Conventional inverted-F antenna is obtained by top-loading a short monopole with a shorted horizontal wire of about a quarter-wavelength. This kind of inverted-F antenna has the advantage of low profile and better matching to 50 Q, and can be mounted above a ground plane or printed on a dielectric substrate [ I ] , [2]. For the latter structure on a dielectric substrate, the inverted-F antenna is capable of integration with the associated circuitry on the same dielectric substrate, which can reduce the fabrication cost and the required volume of the whole system. In this article, we present two promising designs of printed inverted-F antenna. One is a dual-band design for applications in WLAN (wireless local area network, 2400-2484 MHz) and HIPERLAN (high-performance radio local area network, 5150-5350 MHz) systems. The second one is a folded inverted-F antenna printed on a dielectric substrate and fed by a coplanar waveguide (CPW) for UMTS (universal mobile telecommunication system, 1920-2170 MHz) applications. Details of the proposed antenna and experimental results are presented.