-3-Dielectric Resonator Antenna Array at 2.4 GHz

Mohamad Kamal A. Rahim, Mohd Nazri A. Karim, Thelaha Masri, Osman Ayop, Huda Majid, “Dielectric Resonator Antenna Array at 2.4 GHz”, 2008 Asia Pacific Microwave Conference (APMC 2008), 16 - 20 Dec 2008, Macao China.

Introduction:

For many years, the dielectric resonator (DR) has primarily been used in microwave circuits, such as oscillators and filters, where the DR is normally made of high-permittivity material, with dielectric constant > 20. The unloaded Q-factor is usually between 50 and 500, but can be as high as 10,000. Because of these traditional applications, the DR was usually treated as an energy storage device rather than as a radiator. Although open DRs were found to radiate many years ago [1-2], the idea of using the DR as an antenna had not been widely accepted until the original paper on the cylindrical dielectric resonator antenna (DRA) was published in 1983. At that time, it was observed that the frequency range of interest for many

systems had gradually progressed upward to the millimeter and near-millimeter range (100- 300 GHz). At these frequencies, the conductor loss of metallic antennas becomes severe and the efficiency of the antennas is reduced significantly. Conversely, the only loss for a DRA is that due to the imperfect dielectric material, which can be very small in practice. The work created the foundation for future investigations of the DRA. Different shapes of DRA were also studied, including the rectangular, circular, triangular, spherical-cap, and cylindrical-ring DRAs. It was found that DRAs operating at their fundamental modes radiate like a magnetic dipole, independent of their shapes.

Design Consideration Dielectric Resonator Antenna (DRA) Array

The design of the antenna array was started by selecting the suitable dielectric resonator of the antenna. The dielectric resonator shape is cylindrical with a height of 7.5mm, radius of 8.25mm and dielectric constant of 80. This antenna has been designed to operate at 2.4 GHz with input impedance of 50 Ohm, using FR4 (dielectric constant = 4.8) and height (h) of 1.6 mm. Then, the DRA is simulated using the CST software. After the simulation, the DRA is fabricated using FR4, with dielectric constant (dielectric constant = 4.8) and height of 1.6 mm. Finally the DRA is measured using the network analyzer and the measured values were compared with the simulated values. The single element design is shown in figure 2. The dielectric resonator is attached to a 50 Ohm transmission line.