Microstrip feeding for the excitation of a higher-order resonant mode in cylindrical dielectric resonator antennas

摘要

This paper proposes a new feeding scheme for exciting a higher-order resonant mode in cylindrical dielectric resonator antennas. The proposed feeding structure comprises a nonresonant microstrip patch connected to a narrow microstrip line by means of an inset. Both the microstrip patch and line are located under the antenna radiating element (dielectric resonator). A parametric analysis of this feeding structure has been carried out using electromagnetic simulation. The results of this analysis indicate that the antenna impedance matching can be adjusted by changing the length of the inset, and that different values of directivity and impedance bandwidth can be obtained by using different microstrip patch sizes and inset lengths. An antenna prototype has been designed and fabricated to validate the proposed feeding structure using a dielectric resonator with a high dielectric constant. The measured resonance frequency and impedance bandwidth of this prototype are 6.20 GHz and 25.0 MHz (fractional bandwidth of 0.403%), respectively, showing good agreement between simulated and experimental results.