Abstract:
Recently, to solve the huge volume of conventional dielectric resonator antenna (DRA), the innovative low-profile DRAs, such as dense dielectric patch antenna (DDPA) and planar DRA, have been developed, and quickly become the hot spots. However, the existing low-profile DRA designs have disadvantages such as large planar sizes (>0.5λ
0×0.5λ
0) or narrow bandwidths (<10%), which limit their applications. In this paper, a low-profile wideband DRA with a miniaturized planar size is studied. This antenna adopts a dense dielectric patch resonator (DDPR) design, which has a high permittivity dielectric sheet on the top, a low permittivity substrate in the middle, and a slot feeding structure on the bottom. The slot feeding structure can excite two working modes of the DDPR, which are TE
111 and TE
131, respectively. The two modes have very different field distributions at the edge area of the DDPR, that is the E-field distribution of TE
111 is very weak while the E-field of TE
131 is quite strong. Based on the observation, we propose a technique of slightly increasing the height of the edge area of the DDPR, which can significantly affect the TE
131 resonant frequency while slightly affect the TE
111 resonant frequency. With this technique, the resonant frequency of TE
131 mode can be quickly pulled down and merged with that of TE
111 mode. The operating bandwidth, therefore, can be greatly enhanced without increasing the planar size of the DDPR. The size of the antenna is kept as 0.35
λ0×0.35
λ0×0.08
λ0. Measured results show that the linearly polarized antenna prototype has a −10 dB impedance bandwidth of 18.5% and a maximum gain of 7.3 dBi. Simulated results of the 1×5 array show that the antenna is suitable for beam-steering applications. Further, the design concept is extended to a design of circularly polarized antenna, which also has a compact size and an enhanced bandwidth.