This article focuses on reducing mutual coupling between the ports of dielectric resonator antenna (DRA) using defected ground structures (DGSs). The antenna has the dimension of 50 mm × 50 mm × 8.5 mm. The resonating element in the proposed two-port radiator consists of a cylindrical structure of alumina ceramic (ɛr = 9.8). The rectangular-shaped aperture is utilized to excite both of the resonating elements. The resonating ceramic elements acting as radiators are offset-fed to enhance the antenna’s coupling. Combining interdigital-shaped and semicircular arc-shaped DGSs improves isolation between two resonating elements, embodying the structural novelty. The measured operating frequency range of Port-1 and Port-2 is 5.19–6.7 and 5.15–6.68 GHz, resonating at 5.58 and 5.56 GHz, respectively. The measured mutual coupling between the two ports is −35.5 dB. The measured gain for Port-1 is depicted to be 5.5 dB. The presented multiple-input–multiple-output (MIMO) radiator in this article is an appropriate candidate for WLAN (5.25–5.35, 5.47–5.725, 5.725–5.85, 5.850–5.925 GHz) and WiMAX(5.5 GHz) applications. All the simulated and experimentally observed MIMO parameters of the radiator are discovered to be within optimal bounds.

In this paper, we propose a frequency-reconfigurable antenna structure consisting of a dielectric resonator (DR) topped by a superstrate material. Two metasurfaces (MSs) are placed upon the DR and the superstrate, where these two MSs are utilized to synthesize a localized reduction of the dielectric constant of the DR. By placing switches into one of the MSs, the distribution of dielectric constant of the DR can be switched to one of two predefined distributions, which is equivalent to switching the DR length to two different lengths. Consequently, the frequency response of the proposed structure can be tuned to one of two operating bands. The excited modes inside the proposed antenna were obtained analytically and through simulations. Also, the dielectric constant value of substrates topped by MSs was analyzed. The antenna was fabricated and measured, and good agreement between simulation and measurement was attained. The antenna bandwidths are 7–8.1 GHz (14.7%) and 8.5–9.2 GHz (8%) and the gains are 5.1 and 7.8 dB, in the cases of having switches off and on, respectively.

The design and first experimental results of Tx and Rx L-band bandpass filters for a high-power satellite diplexer are presented in this paper. Designed in the framework of an ESA ARTES AT project, the filters are based on TM010 mode dielectric resonators. These resonators allow for better results in terms of volume occupation with respect to other dielectric resonators still maintaining high Q-factor values (>2000). Volume saving above 30% is achieved with respect to standard coaxial filters. The filter geometries and materials have been chosen in order to improve the power-handling and to cope with related critical issues for space applications (i.e. avoid any multipactor discharge in the operating RF power range and low-PIM response). Measurements of Tx filter show good correlation with the design in terms of central frequency, BW, and unloaded Q-factor (almost 3000). Measurements of Rx filter show a worse correlation with the design in terms of filter response shape. This is ascribed to size tolerances of one of the filter resonators. Multiple analyses are ongoing to remove this degradation in the final engineering model.

A bidirectional dielectric resonator (DR) antenna array using back-to-back quasi-Yagi antenna configuration is proposed and implemented for the first time. The DR operating at higher-order TE3δ1 mode is used as a magnetic dipole, applying for the driver of quasi-Yagi antenna. Due to the high-order mode employment, the antenna gain can be enhanced. By partially loading the metallic strip on the side wall of the DR, the gain can be further enhanced. In addition, a simple dual Marchand balun is constructed for feeding the two quasi-Yagi antennas directly for bidirectional radiation. To verify the design concept, a prototype operating at the X-band is fabricated and measured. Good agreement between the simulated and measured results can be observed.

In this paper, a novel multilayer substrate integrated dual-mode dielectric resonator (DR) filter is proposed. The square dual-mode DR is made of the high permittivity substrate by removing the undesired portions and the surface coppers so that the relatively high unloaded quality factor of the dominate TM11 pair can be obtained which compared to these fully dielectric-filled substrate integrated waveguides. Meanwhile, it can be easily integrated in an equivalent cavity implemented by multilayer printed circuit boards for filter design, showcasing low in-band loss, light weight, and compact size. For demonstration, a multilayer substrate integrated DR bandpass filter centered at X-band is designed and measured. Good agreement between the simulated and measured results can be observed, and the measured insertion loss at the passband center frequency (8.38 GHz) is 1.1 dB.

A new structure of Q-band filter comprising rectangular high-permittivity dielectric resonators (DR) operating at TM11δ mode is introduced. The resonator shows high-quality factor (Q) and wide spurious free window compared with other technologies available at Q-band for realizing filters. Low permittivity ceramic material (quartz) is used as a support for holding DR at the center of the cavity. An eight-pole cross-coupled band-pass filter having a bandwidth of 225 MHz at 38.5 GHz was realized. Resonant coupling structure is introduced to realize cross-coupling in filter. The resonator assemblies were optimized precisely to achieve effective linear frequency drift over temperature of the order of 2 ppm/°C. The filter also survived severe sine and random vibration test for satellite application.

In this paper, we present a near-field microwave microscopy method for the characterization of dielectric materials samples in the Industrial, Scientific and Medical (ISM) band. The system proposed is composed of a probe coupled to a dielectric resonator (DR) operating in the TE011 mode. Latter this is used to fix the resonance frequency of the resonator at 2.45 GHz. This system is used for the characterization of dielectric samples with accuracy and high spatial resolution, knowing that they do not have predetermined forms, but a small plane surface.The same device is used for a multi-frequency characterization (4–20 GHz) using resonance frequencies of the cavity instead of one resonance frequency of the DR.