Xiaosheng Fang

Designs of Single-, Dual-, Wide-Band Rectangular Dielectric Resonator Antennas

Designs of the single-, dual-, wide-band rectangular dielectric resonator antennas (DRAs) are discussed. Using new single-band formulas, the resonance frequency of the DRA can be determined easily from the given DRA dimensions and vice versa. Also, new formulas for designs of dual-mode rectangular DRAs are derived in this paper. From the derivation, the limit of the frequency ratio is also found and discussed. The formulas can be used to design a dualband DRA or a wideband DRA when the two resonance frequencies are close to each other. To validate our results, three single-, dual-, and wide-band rectangular DRAs were designed using the new formulas. In each case, the reflection coefficient, radiation pattern, and antenna gain were simulated and measured. Good agreement between the calculated, simulated, and measured results is obtained.

The Compact Circularly-Polarized Hollow Rectangular Dielectric Resonator Antenna With an Underlaid Quadrature Coupler

The wideband circularly polarized (CP) dielectric resonator antenna (DRA) is investigated with an underlaid quadrature coupler. The idea is used to realize a CP hollow rectangular DRA. Since the coupler is located beneath the DRA, it does not increase the footprint of the antenna, making the system very compact. The underlaid coupler is placed entirely inside the hollow region of the DRA and, thus, it can be designed easily as if there is no overlaid DRA. Two configurations are considered in this paper. In the first configuration, an external 50-Ω load is used for the matching port of the coupler. For the second one, a strip loaded by the DRA is used to provide a load and, thus, no lumped elements are required in this configuration. In this paper, a network model is also given to aid engineers in designing the proposed integrated DRA. The reflection coefficient, axial ratio, antenna gain, and radiation pattern for each configuration are studied. It was found that wide impedance and axial-ratio bandwidths can be obtained with the proposed CP DRAs. Measurements were carried out to verify the simulations, and reasonable agreement between them was obtained.

Singly-Fed Dual-Band Circularly Polarized Dielectric Resonator Antenna

This letter presents a new dual-band circularly polarized (CP) dielectric resonator antenna (DRA). The dual-band design utilizes the quasi- TE111 and -TE113 modes of the rectangular DRA, which is coupled by a simple underneath rectangular aperture. Two opposite corners of the DRA are removed at 45° to obtain CP fields. A diagonal groove is introduced at the top face of the DRA to facilitate tuning of the DRA. A design guideline of the dual-band CP DRA is given. The reflection coefficient, radiation pattern, axial ratio, and antenna gain of the DRA are simulated and measured, with good agreement between them.

Compact Differential Rectangular Dielectric Resonator Antenna

In this letter, a compact differential hollow dielectric resonator antenna (DRA) is investigated. The hollow DRA is fed by two identical conducting strips connected to the outputs of an underlaid 180° hybrid coupler (rat-race). With this compact configuration, loss of the feed network can be minimized and, thus, the differential gain can be made about the same as for the single-ended case. By using the differential feed, the DRA can be integrated with differential integrated circuits directly. Also, its cross-polarized fields are generally weaker than those of the single-ended version. The reflection coefficient, radiation pattern, and antenna gain of the proposed differential DRA are simulated, and the result agrees reasonably with our measurement.

Dual-Function Radiating Glass for Antennas and Light Covers—Part II: Dual-Band Glass Dielectric Resonator Antennas

This paper is the second part of our study that investigates using glass dielectric resonator antennas (DRAs) as light covers. To begin, designs of dual-band hemispherical DRAs are investigated for the first time. Both broadside and omnidirectional dual-band DRAs are included in the study. The former makes use of the broadside TE111 and TE112 modes of a hollow hemispherical DRA, whereas the latter utilizes the endfire TM101 and TM103 modes of a solid hemispherical DRA. New design formulas that determine the radii of the two dual-band hemispherical DRAs are found. To demonstrate the usefulness of the formulas, two dual-band hemispherical DRAs for WLAN/WiMAX applications were designed and fabricated using K9 glass. ANSYS HFSS was used to simulate the DRAs, and the results agree reasonably well with our measurements. Results of using the DRAs as light covers are reported.

On the wideband notched rectangular dielectric resonator antenna

The strip-fed wideband notched rectangular dielectric resonator antenna is investigated in this paper. By simultaneously exciting the TE<inf>111</inf>^y and TE<inf>113</inf>^y modes of the DRA, a wide impedance bandwidth of 56% can be obtained, which entirely covers the WLAN (2.4–2.48 GHz) and WiMAX (3.4–3.7 GHz) bands. The reflection coefficient, radiation patterns, antenna gain and efficiency of the antenna were studied. Reasonable agreement between the simulated and measured results is obtained.

Wideband two-layer transparent cylindrical dielectric resonator antenna used as a light cover

This paper investigates a wideband cylindrical transparent dielectric resonator antenna (DRA), working as a light cover. The antenna is made of transparent materials. To broaden its bandwidth, two layers of transparent materials with different dielectric constants are put together. The lower layer has a hollow region for the accommodation of an LED light source. The VSWR, radiation pattern, and antenna gain are simulated and measured. Results show that it can simultaneously work as an antenna and a light cover, with negligible effects of the LED light source on the antenna performance.