Search

A high-efficiency dual-band dielectric filtering antenna based on three parallel placed dense dielectric strip resonators (DDSRs) is proposed for the self-filtering property. That means both the filtering responses of the two bands are only determined by the three DDSRs themselves without extra filtering circuits. The even-mode coupling of the TM1δ mode (TM3δ mode) between the middle and two-sided DDSRs is used to form the first (second) radiation band, while the odd-mode coupling contributes one radiation null at the upper edge of each radiation band. Therefore, the proposed dual-band dielectric antenna exhibits relatively high total efficiency benefited from the self-filtering characteristic. Additionally, the presented one without extra filtering circuits obtains the features of low profile, enhanced bandwidth, and gain. For test and verify, a prototype was measured at 7.7 and 13.35 GHz with the fractional bandwidths of 11.4% and 4.8%, the peak gains of 7.65 and 10.5 dBi, and the total efficiencies of 89% and 87%, respectively. Radiation nulls are generated at 8.5 and 13.8 GHz, respectively. [ABSTRACT FROM AUTHOR]

This brief presents a new kind of adjustable dielectric waveguide resonator (DWR), based on which integrated designs of filtering circuits are conducted. The DWR is composed of a dielectric part as the main resonating body and a printed circuit board (PCB) part as the cover. An unmetallized blind hole is carved at the upper surface of the dielectric part. A tuning screw is installed on the PCB and inserted into the unmetallized blind hole to adjust the resonant frequency the DWR. This adjusting method is flexible and reversible. By using the proposed adjustable DWR, a fourth-order bandpass filter (BPF) is designed, fabricated and measured. The measured results show that the BPF is with an in-band insertion loss of 0.8 dB and an in-band return loss better than 19 dB. A capacitive cross coupling structure is constructed on the PCB so that two transmission zeros are introduced close to the passband to improve the filtering selectivity. In addition, a Wilkinson power divider is realized on the PCB and integrated with the above BPF, forming a filtering power divider. The measured in-band insertion loss of the filtering power divider is 1.1 dB. The isolation is better than 24 dB and the maximum phase imbalance is 1° in the passband. [ABSTRACT FROM AUTHOR]

The performance of a low-profile dielectric resonator (DR) antenna (DRA) is hardly maintained across a wide frequency range due to the multiple higher-order modes. In this letter, a low-profile and broadband DRA is proposed with stable broadside radiation over a wide range of frequencies. A detailed analysis of the excited modes is conducted to identify proper modes for broadband operation. Different air regions are then introduced in the top layer of the proposed DRA. This allows the excitation of the higher-order DR modes with broadside radiation while suppressing the unwanted off-boresight modes. To validate the design, the DRA is developed to cover the frequency range of 3.25–6.1 GHz for potential 5G applications. The fabricated prototype is measured showing a broad bandwidth of ∼64.2%, a peak antenna gain of ∼9 dBi, and a low profile of only ∼0.07λ0. [ABSTRACT FROM AUTHOR]

In this letter, a circularly polarized antenna featured with a low profile, wideband, and high gain is investigated. The antenna, looking like a classical stacked microstrip patch antenna (MPA), is essentially a stacked dielectric resonator antenna (DRA) with high permittivity thin dielectric slabs introduced instead of metallic patches. With this structure, the antenna can take advantages of both MPA and DRA, showing superior performance than either of them. On this basis, a polarization-reconfigurable antenna version is further proposed with three polarization states of right-handed (RH), left-handed (LH) circular polarization (CP) and linear polarization. For demonstration, antenna prototypes were fabricated and measured. Reasonable agreement between the measured and simulation results is observed. [ABSTRACT FROM AUTHOR]

A dielectric patch (DP) resonator (DPR) with silver-coated slots is investigated for designing wideband low-profile antenna in this communication. The low-profile DPR can be treated as an anisotropic dielectric resonator (DR) for analysis. A new equation for calculating the effective dielectric constant of the DPR operating at the TM modes is proposed. Based on this, the anisotropic property is investigated to enhance the gain of DP antenna (DPA). It is found from the theoretical analysis that the resultant antenna is a good compromise between the traditional microstrip patch antenna (MPA) and dielectric resonator antenna (DRA) in terms of profile, gain, efficiency, and design freedom. By making full use of the multimode characteristic of the DPR, the silver-coated slots are introduced on the DP to shift high-order TM121 mode close to TM101 mode. As a result, the bandwidth of the antenna can be significantly expanded. For demonstration, the DPA element and $1\times4$ array prototype operating in the microwave band (5 GHz) are implemented and measured. [ABSTRACT FROM AUTHOR]

A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide coupling slot from the bottom. The stacked DRA structure, with high-permittivity dielectric strips layered on low-permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a $2 \times 2$ subarray are further presented. To verify the design, a subarray prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1 dB AR bandwidth of 15.6%, and a peak gain of 15.1 dBi. [ABSTRACT FROM AUTHOR]

A kind of circular polarized (CP) stacked dielectric resonator (DR) antenna with wide bandwidth and high gain is presented in this communication. For this design, a two-layer DR with improved performance in bandwidth and gain is used as the basic resonator. By further applying it into a stacked design, two similar modes with adjacent resonant frequencies can be merged together, providing a wide axial ratio bandwidth of more than 20%. The single-feed CP operation is achieved by adopting a coupling cross-slot, which is beneficial for fine-tuning and array forming, as compared to multifeed structures. Two design examples working at different frequency bands and for different senses of CP have been presented to demonstrate the effectiveness of the design concept. [ABSTRACT FROM AUTHOR]

A novel self-packaged circularly polarized (CP) dielectric resonator antenna with wide bandwidth and high gain is proposed. To obtain a low-profile antenna structure, one strip dielectric resonator (DR) is integrated entirely inside the hollow region of the other two-layer DR. Two coupled CP modes from the composite DR structure are simultaneously excited, constituting a wide operating bandwidth. The proposed antenna also has a high-radiation gain by taking advantages of the substrate integrated waveguide (SIW) based air cavity and the high-gain nature of the adopted two-layer DR. Measured results of the antenna prototype indicate that the design can achieve an overlap bandwidth of 28.6%, with a peak gain of 11.3 dBi. [ABSTRACT FROM AUTHOR]

This communication presents a differential dual-band dual-polarized dielectric resonator antenna (DRA) with high isolation and low cross polarization using a cross-shaped DR. In the differential DRA, some of the higher order modes are eliminated and electromagnetic fields of each excited mode have no interaction with its corresponding orthogonal mode. Two groups of modes are utilized to realize dual-band characteristic and each group with two orthogonal modes is used to supply dual-polarized function. Differential feeding provides the DRA with suppression of unwanted modes, much higher isolation and lower cross-polarization in both frequency bands, compared with the traditional single-end feeding. The experimental prototypes of the proposed differential DRA and its single-ended counterpart are designed and implemented. The comparison between them is also made in reflection coefficient, isolation, and radiation properties. Both simulated and measured results show significantly improved performance of the proposed differential DRA. [ABSTRACT FROM PUBLISHER]

A square dielectric patch (DP) resonator fusing with the bottom substrate is studied for designing low‐profile circularly polarized (CP) antenna. Based on the theoretical investigation using the constructed analysis model, it can be found that the proposed DP resonator possesses a pair of degenerate dominate modes (TM101 and TM011), which can be split by introducing perturbations on the DP resonator and then used to design CP antenna fed by a microstrip line directly. To verify the proposed idea, a 2 × 2 array fed by a dual Marchand balun network is designed and implemented. Reasonable agreement between the measured and simulated results is observed. Experimental results show that a measured impedance bandwidth is 380 MHz (5.18‐5.56 GHz) for |S11| < −10 dB and the 3‐dB axial ratio bandwidth is 90 MHz (5.32‐5.41 GHz). The measured gain is up to 11.77 dBic with a cross polarization of about −20 dB in the boresight direction. [ABSTRACT FROM AUTHOR]