This paper presents a wideband dielectric resonator antenna (DRA) with a stable gain in-band. Four modes are excited in the DRA, including the fundamental mode TE 111 (y) and higher-order modes TE ...113 (y), TE 122 (z) and TE 115 (y), which are combined to provide a wide impedance bandwidth. However, this combination of modes introduces severe gain drops at specific frequencies, resulting in a fluctuating gain across the wide impedance bandwidth. To improve the gain bandwidth, the electric filed distributions at these specific frequencies are analyzed and reconstructed using the proposed approaches. For demonstration, a practical prototype of the proposed antenna is fabricated and measured. Reasonable agreement between the measured and simulated results is observed. The prototype exhibits a wide measured 10-dB impedance bandwidth of 64.6 % (5.85~11.48 GHz) and a 1-dB gain bandwidth of 57.5% (6.35~11.48 GHz), with stable broadside radiation patterns in-band. Additionally, the maximum gain can reach 7.2 dBi.
In this letter, a three-port omnidirectional cylindrical dielectric resonator antenna (DRA) is presented. The design makes use of the TM 01 δ and two degenerate HEM 21 δ modes of the cylindrical DRA. ...The resonant features of the two modes are investigated and their resonant frequencies are different. The TM 01 δ mode is fed with horizontal magnetic current, which is obtained by four slots. The input impedance of the antenna is affected by the length of the open-circuit stub, which is the end of the feed network. Thus, the resonant frequency of the TM 01 δ mode can be moved to that of the HEM 21 δ one through the proposed exciting method. Two HEM 21 δ modes are excited simultaneously by a 90° hybrid coupler to realize right- and left-hand circularly polarized omnidirectional radiation. Based on the three modes, a three-port three-polarization DRA with omnidirectional radiation for indoor communication applications is fabricated and measured. The results indicate that the S -parameters, field characteristics, and communication performance are satisfactory in the operating band.
A substrate integrated differential cavity-backed dual-polarized dielectric resonator antenna with a wide bandwidth, low profile, high isolation, and improved gain is presented. The proposed ...substrate integrated technique, in which the electric and magnetic walls of the cross-shaped dielectric resonator antenna (DRA) are realized by arrays of metallic and nonmetallic vias, respectively, provides the design with high level of integration and low profile. The substrate integrated DRA is differentially fed by microstrip lines through coupling slots exciting a pair of orthogonal modes for the dual polarizations. The differential feeding scheme offers a direct connection to differential systems, and greatly improves the isolation between polarizations. Benefitting from the differential coupling slots and the substrate integrated back cavity, the bandwidth is broadened and the realized gain is improved. For demonstration, a prototype is designed and fabricated. The simulated and measured results show a good agreement.
•Novel locally-resonant inertant plate with tunable fixed inerter-based resonators.•Resonator including inerter and spring in parallel, connected to the plate by a single spring.•Inertance/stiffness ...of resonator tunable by rhombus trusses with telescopic rods.•Ultra-wide band gap opened at very low frequency for structural/mechanical applications.•Band-gap opening frequency and width change with diagonal ratios of rhombus trusses.
A novel concept of locally-resonant inertant plate is presented. The key idea is that the plate is supported by a periodic array of fixed one-degree-of-freedom inerter-based resonators, where each resonator consists of an inerter and a spring acting in parallel, connected to the plate by a single spring. Further, the resonator is tunable by two rhombus trusses with telescopic rods, allowing changes of inertance and stiffness. The relevant result is that, because of local resonance and periodicity, a very large band gap can be opened at very low frequency, which is of remarkable interest for structural and mechanical engineering applications. Additionally, opening frequency and width of the band gap can be changed by appropriate selections of the diagonal ratios of the rhombus trusses. The wave propagation analysis is carried out by a finite-element model in ABAQUS. Dispersion curves and frequency response under various loading conditions substantiate the effectiveness of the novel concept of locally-resonant inertant plate.
In this paper, a new type of microwave microfluidic sensor is presented, using three separate half wave microstrip resonators with a common junction. The sensor comprises three parallel resonators ...with resonant frequencies of 2.5, 3.5, and 4.5 GHz. This sensor exhibits all the usual advantages of microwave resonant methods for dielectric liquid characterization, such as high precision, accuracy, and sensitivity, but here also over a wideband of frequencies. The resonators have common input and output ports. The sensor was tested using several types of liquids, including water, methanol, ethanol, and chloroform, and experimental results are in excellent agreement with the simulation results.
This letter presents a 0.43 GHz/0.9 GHz/1.575 GHz/ 2.45 GHz quadruplexer with ripple bandwidth of 40 MHz/ 70 MHz/60 MHz/100 MHz using a common lumped-element quadruple-mode resonator (LE-QMR). One ...resonant mode from LE-QMR and two resonant modes from two <inline-formula> <tex-math notation="LaTeX">LC </tex-math></inline-formula> resonators constitute every channel of the proposed quadruplexer. The dual-plane structure configuration is employed in this design to relieve the limited physical space. A step-to-step design procedure is given to validate our design approach. The measured result shows that the fabricated quadruplexer exhibits low insertion loss, up to 40-dB port-to-port isolation and compact size of <inline-formula> <tex-math notation="LaTeX">0.071\lambda _{g}\times 0.097\lambda _{g}\times 0.002\lambda _{g} </tex-math></inline-formula>.
The primary focus of this work is to fabricate and evaluate electroceramic based LC resonators for wireless sensing at high temperatures. An all-ceramic planar LC resonator was fabricated on a ...polycrystalline Al 2 O 3 substrate by using tin-doped indium oxide (ITO) as the electrode material. The LC resonators were deposited on the substrate by a novel two-step micro-casting technique. The resonator was designed using the ANSYS Maxwell package to operate within a wide frequency bandwidth from 10 to 80 MHz. A similar all-ceramic inductor was fabricated and used as the interrogator antenna to collect the wireless response at high operating temperature. The wireless characterization was performed by a radio frequency (RF) signal generator and an in-situ spectrum analyzer from 500 - 1200°C. The microstructural, chemical, and electrical stability of the LC resonator was investigated by SEM, 4-point conductivity, and XRD. Additionally, a robust adaptive signal processing algorithm was developed to analyze the wireless response of multiple LC resonator. The adaptive algorithm developed in this work is data driven and does not require a predefined model to analyze the wireless response from the LC resonator.
Compact dual-band dual-channel bandpass filters (BPFs) with different and identical frequency allocations are presented in this paper. Because of the magnetic boundary condition, four resonant modes ...are excited in the dielectric resonator (DR). The excitation and coupling scheme are analyzed and therefore dual-passband with different frequencies and bandwidths are obtained in each channel. Moreover, benefiting from the two pairs of orthogonal degenerate modes and excitation principle, the high isolation between the two channels is guaranteed. For verification, two dual-band dual-channel BPFs are designed. With only two DRs and two sets of probes, low insertion loss and high isolation better than 38 dB are achieved in the dual-band dual-channel BPF with the same passbands. It demonstrates that the proposed method would replace four conventional BPFs in the massive input massive output communication systems and the volume and number of resonators could be remarkably reduced.
This paper presents the design of a compact dual‐band bandpass filter (DB‐BPF) with flexible passband frequencies and sharp skirt. A pair of stub loaded stepped‐impedance resonators (SL‐SIRs) ...together with two different tri‐section stepped‐impedance resonators (TS‐SIRs) constitute this DB‐BPF. The low impedance sections of two SL‐SIRs and one TS‐SIR are realized by ring structure, on the one hand to acquire two independent resonant modes of SL‐SIRs, and on the other hand to let the harmonic mode of TS‐SIR be away from the upper passband. The cross coupling, the canceling effect of mixed electric and magnetic coupling (MEMC), and the virtual ground introduce the TZs, resulting in the sharp skirt property of proposed DB‐BPF. Step‐to‐step design process is given to guide the DB‐BPF design. As an example, a 0.9 / 1.8 GHz DB‐BPF is designed and fabricated. The fabricated sharp skirts DB‐BPF has a compact size of 0.079λg × 0.193λg, low passband loss of 0.84 / 0.98 dB and high band‐to‐band rejection of better than 40.6 dB.
A new approach for the design of a balanced bandpass filter (BPF) is presented in this paper. Stemming from the mode degeneration properties of a square patch resonator, a complete set of resonant ...modes in a right-angled isosceles triangular patch resonator (RAITPR) is thoroughly investigated so as to construct a modified RAITPR with one electric wall and two magnetic walls along its three sides for filter design. This proposed resonator can support the half-TM 10 -mode of the RAITPR, and thus, it is named as the half-mode RAITPR here. By properly adopting the relationship between one RAITPR and two coupled half-mode RAITPRs, a second-order coupling topology is presented. Its working principle is then explained by using the field distribution of the desired resonant modes involved. A few high-order balanced filters are in final implemented and fabricated to evidently demonstrate their good differential-mode filtering selectivity and high common-mode suppression. Good agreement is achieved between the simulated and measured results for all the designed three balanced BPFs. To further improve the concerned out-of-band rejection performance, the feeding scheme of the modified structure has been discussed.
