A novel Multi-permittivity Cylindrical Dielectric Resonator Antenna for Wideband Applications

In this paper, a novel multi-permittivity cylindrical dielectric resonator antenna for wideband application is presented. The multi-permittivity cylinder is formed by combining two different permittivity material sectors in such a way that each sector (with constant permittivity) is 90 degree apart. A direct microstrip line coupling terminated with T-stub at the open end is used to excite the multi-permittivity cylindrical dielectric resonator. The angular position of the multi sector dielectric resonator with respect to the longitudinal axis of the microstrip line and length of the additional strip at the open end of the feeding circuit is key parameters for wideband operation of the antenna. By optimizing all parameters of the proposed antenna, wideband impedance bandwidth of 56% (12.1 GHz - 21.65 GHz) is achieved. The average gain of the antenna throughout the bandwidth is 5.9 dB with good radiation properties in both E-plane and H-plane. A well matched simulation and experimental results show that the antenna is suitable for wideband applications

Comparison of Power Dependence of Microwave Surface Resistance of Unpatterned and Patterned YBCO Thin Film

The effect of the patterning process on the nonlinearity of the microwave surface resistance $R_S$ of YBCO thin films is investigated. With the use of a sapphire dielectric resonator and a stripline resonator, the microwave $R_S$ of YBCO thin films was measured before and after the patterning process, as a function of temperature and the rf peak magnetic field in the film. The microwave loss was also modeled, assuming a $J_{rf}^2$ dependence of $Z_S(J_{rf})$ on current density $J_{rf}$. Experimental and modeled results show that the patterning has no observable effect on the microwave residual $R_S$ or on the power dependence of $R_S$.Comment: Submitted to IEEE Trans. MT

Circularly polarized dielectric resonator antenna excited by a conformal wire

A conformal spiral wire has been used to feed a dielectric resonator antenna to obtain a circular polarization. The parameters of the spiral have been optimized numerically so that minimum axial ratio (AR) and return losses are achieved. The method of moments (MoM) has been used in the analysis and the results have been validated against those from a commercial software package with a good agreement

Wideband P-Shaped Dielectric Resonator Antenna

A novel P-shaped dielectric resonator antenna (DRA) is presented and investigated for wideband wireless application. By using P-shaped resonator, a wideband impedance bandwidth of 80% from 3.5 to 8.2 GHz is achieved. The antenna covers all of wireless systems like C-band, 5.2, 5.5 & 5.8 GHz-WLAN & WiMax. The proposed antenna has a low profile and the thickness of the resonator is only 5.12 mm, which is 0.06-0.14 free space wavelength. A parametric study is presented. The proposed DRA is built and the characteristics of the antenna are measured. Very good agreement between numerical and measured results is obtained

A singly fed rectangular dielectric resonator antenna with a wideband circular polarization

A rectangular dielectric resonator antenna (DRA) that is excited using an outer-fed square spiral strip has been studied theoretically and experimentally. Utilizing such excitation has provided a circular polarization over a broad bandwidth of ${sim 14}$ in conjunction with an impedance-matching bandwidth of ${sim 11}$. The structure has been rigorously modeled using a method of moments (MoM) model. A good agreement has been attained between computed and measured results

Complex Permittivity Measurements at Variable Temperatures of Low Loss Dielectric Substrates Employing Split Post and Single Post Dielectric Resonators

A split post dielectric resonator in a copper enclosure and a single post dielectric resonator in a cavity with superconducting end-plates have been constructed and used for the complex permittivity measurements of single crystal substrates. (La,Sr)(Al,Ta)O3, LaAlO3, MgO and quartz substrates have been measured at temperatures from 20 K to 300 K in the split post resonator and from 15 K to 80 K in the single post resonator. The TE01delta mode resonant frequencies and unloaded Qo-factors of the empty resonators at temperature of 20 K were: 9.952 GHz and 25,000 for the split post resonator and 10.808 GHz and 240,000 for the single post resonator respectively.Comment: 4 pages, 8 figures, 1 tabl

A New Wideband Circularly Polarized Dielectric Resonator Antenna

A wideband and compact circularly polarized (CP) C-shaped dielectric resonator antenna (DRA) is presented. The proposed C-shaped DR is excited by a simple stripe line connected to a coplanar waveguide (CPW) feeding line. The C-shaped DRA is circularly polarized with 19% axial ratio (AR) bandwidth. It is found that the CP bandwidth can be expanded by using a narrow short circuit strip. The final design achieves CP with 50% AR bandwidth. The proposed circularly polarized DRA (CPDRA) with good radiation characteristics offers an impedance bandwidth of 58% between 3.45 and 6.26 GHz for VSWR ≤ 2. The proposed DRA is fabricated and tested. Very good agreement between simulated and measured results is obtained

A wideband trapezoidal dielectric resonator antenna with circular polarization

A new design of a circularly-polarized (CP) trapezoidal dielectric resonator antenna (DRA) for wideband wireless application is presented. A single-layered feed is used to excite the trapezoidal shaped dielectric resonator to increase resonant frequency and axial ratio. Besides its structure simplicity, ease of fabrication and low-cost, the proposed antenna features good measured impedance bandwidth, 87.3% at 4.21 GHz to 10.72 GHz frequency bands. Moreover, the antenna also produces 3-dB axial ratio bandwidth of about 710 MHz from 5.17 GHz to 5.88 GHz. The overall size of DRA is 21 mm × 35 mm, which is suitable for mobile devices. Parametric study and measurement results are presented and discussed. Very good agreement is demonstrated between simulated and measured results