Magnetic tuning of cylindrical H01δ-modedielectric resonators

The theory of magnetic tuning of cylindrical H_01δ dielectric resonators is developed. It is based on rigorous solutions to the dielectric resonator systems containing microwave ferrites. It is shown that the most effective magnetic tuning of H_01δ dielectric resonators can be accomplished by inserting a thin ferrite rod through an axial hole in the resonator. This kind of tuning utilizes the dependence of the parallel permeability tensor component μ_z on the magnetic field applied. Experiments have been performed which show that a 4% tuning range can be attained with a Q-factor of the resonant system of the order of 2000 at X -band. Using an appropriate DC magnetic field circuit, a 120 MHz tuning bandwidth has been obtained with a consumption of tuning power of about 75 mW     

A Proposal of a New Dielectric Resonator Construction for MIC's

A compact and high-temperature-stable dielectric resonator having no shielding metal walls nor a conventional frequency tuning screw is described. This resonator consists of a high epsilon/sub r/ dielectric resonator element mounted on a low-loss dielectric mount, a dielectric disk with thin metal film fixed on the resonator element, and a microstrip line substrate on which to mount the constituents. The resonant frequency tuning is made by trimming the metal film on the disk. The TE/sub 01delta/ -mode resonant frequencies are analyzed through dielectric waveguide model application. Less than 1-percent analytical error is presented in comparison with the experimental data for a practical resonator. The frequency tuning limit by metal film trimming is about 7 percent. The unfoaded Q value of 2700 at 8.8 GHz and a 4.4-ppm/deg frequency temperature coefficient are obtained.     

Dielectric resonator with discrete electromechanical frequency tuning

A novel approach for discrete frequency tuning of dielectric resonators based on electromechanical actuators such as the microelectromechanical system is presented. The concept is based on the intermodal coupling between the TE/sub 01/spl delta// mode of a cylindrical dielectric resonator and the radially arranged planar slotline resonators. The resonance frequency of the dielectric resonator is changed by switching a resistive load at the open end of each quarter-wave slotline resonator leading to a variation of the coupling between the slotline resonator mode and the TE/sub 01/spl delta// mode of the dielectric resonator. As a consequence, the resonance frequency of the TE/sub 01/spl delta// mode changes. Based on this novel tuning concept, discrete tuning by 5 MHz in 0.25-MHz frequency steps was demonstrated for a test resonator at 2 GHz. The unloaded quality factor is about 12000 and the measured switching time is about 1 ms.     

UHF double dielectric resonator filter with linearised tuning range

A UHF double dielectric resonator filter operating in the TE_01δ mode has been constructed with a high Q, wide (14%) and reasonably linear tuning range. This has been achieved by varying the gap between the resonators, and using the influence of the end wall on the movable resonator. The experimental device is readily scaleable to the cellular radio wave bands     

Precise computations of resonant frequencies and quality factorsfor dielectric resonators in MICs with tuning elements

In this paper, the highly accurate results of resonant frequencies, field distributions, and quality factors of the TE_01δ mode for the cylindrical shielded dielectric resonator (DR) in microwave integrated circuits (MIC's) with a practical tuning element, such as the metallic tuning screw and the dielectric tuning device, are presented. By using the newly developed FD-SIC method, numerical results can be calculated accurately and efficiently. The DR structures with tuning elements can be more easily modeled by the present approach than the other methods using approximate solutions or the mode-matching (MM) methods. Numerical results in the literature are compared to the present FD-SIC results for the DR without tuning elements and detailed discussions on these results are given. In addition, design curves are also presented for the DR with the metallic tuning screw and with the dielectric tuning device. These design curves are helpful for designing DR systems with tuning elements in MIC applications     

Piezoelectrically tuned dielectric resonators

A simple technique for rapid tuning of a dielectric resonator using piezoelectric actuation is described. Results are presented for three dielectric resonator materials with relative permittivities of 9.5, 47 and 100 and dielectric Q-factors of 50000 (10 GHz), 9000 (5 GHz) and 16000 (3 GHz). The advantage of the proposed tuning method is that little degradation in the device Q-factor is observed even with tuning up to 2%     

Rigorous analysis of novel dielectric resonator filters with printed tuning septum

This paper describes the analysis of dielectric resonator filters with printed tuning septum in waveguide sections operating below cutoff. In this design approach a thick dielectric slab of high permittivity is placed longitudinally in the waveguide. A bilateral ladder-shaped metallization determines the resonator and coupling sections (modified finline filter). In contrast to conventional dielectric resonator filters, this approach provides better passband separation and increased stopband attenuation. Furthermore, due to the bilateral tuning septum, the resonator and coupling sections can be manufactured accurately with photolithographic techniques rather than by expensive machining.     

Tunable Dielectric Resonator Bandpass Filter With Embedded MEMS Tuning Elements

This paper presents a novel approach for constructing a tunable dielectric resonator bandpass filter by using the microelectromechanical system (MEMS) technology. The tunability is achieved by unique MEMS tuning elements to perturb the electrical and magnetic fields surrounding the dielectric resonators. The use of such elements as a tuning mechanism results in a wide tuning range at a relatively low tuning voltage and fast tuning speed. A three-pole tunable dielectric resonator bandpass filter is designed, fabricated, and tested. The experimental filter has a center frequency of 15.6 GHz, a 1% relative bandwidth, and an unloaded Q of 1300. A tuning range of 400 MHz is obtained by using MEMS tuning elements with 2 mmtimes2 mm tuning disks. The measured results demonstrate the feasibility of the proposed concept     

Cylindrical Dielectric Resonators and Their Applications in TEM Line Microwave Circuits

A cylindrical sample of low-loss high epsilon/sub r/ placed between two parallel conducting plates perpendicular to the sample axis forms a microwave resonator. A simple approximate method for predicting the resonant frequencies of the TE modes of this structure is developed. The method becomes exact for the fitting case of this structure which is known as a dielectric post resonator. In all cases, the accuracy of the method is shown to be better than 3.5 percent. The TE/sub 01delta/ mode chart presented allows the determination of the resonant frequency and the tuning range of any cylindrical dielectric resonator for which epsilon/sub r/ >or= 10. The properties of the dielectric resonator as a TEM line element are demonstrated experimentally.     

Wavelength-Tunable Microring Resonator on Lithium Niobate

A wavelength-tunable microring resonator with integrated microheater on lithium niobate is presented. Ridge structure on lithium niobate is formed by a wet-etching technique for enhancing the lateral index contrast of the waveguide. The resonant wavelength of the microring resonator is tuned through thermooptic effect by injecting current into the integrated microheater. The tuning characteristics of through port and drop port are measured and the tuning rates in the microring resonator with a radius of 100 mum for transverse-magnetic and transverse-electric polarizations are 2.54 x 10^-2 nm/mA and 3.40 x 10^-3 nm/mA.     

Dual electric and magnetic frequency tuning of coupled oscillations in a composite magnetodielectric resonator

The possibility of dual magnetic and electric tuning of resonance frequencies of the electrodynamic structure consisting of dielectric resonator and the epitaxial film of Yittrium-Iron Garnet (YIG)- lead zirconate titanate (LZT) heterostructure has been shown. The coupled electromagnetic-andspin oscillations of dielectric resonator and epitaxial YIG film were theoretically and experimentally investigated. The experiments revealed the possibility of implementing the electric frequency tuning of coupled oscillations of a composite magnetodielectric resonator. This possibility is determined by induced elastic stresses in the epitaxial YIG film. A theoretical model is proposed for calculating the frequency shift of coupled oscillations caused by the electric field applied to the piezodielectric layer. It is shown that the basic Q-factor of composite resonator and the range of electric frequency tuning of hybrid oscillations increase with the reduction of the magnetic bias field.     

A generalized equivalent circuit applied to a tunablesapphire-loaded superconducting cavity

A Langrangian technique is used to develop an equivalent circuit for a loop-coupled tunable sapphire-loaded superconducting cavity resonator (T-SLOSC) by considering separately the sapphire dielectric and the cavity. Interaction between modes during tuning is characterized by cross coupling components between equivalent mode circuits. Cross-coupling coefficients are defined with respect to the fields in the resonator and equivalent circuit components. Coupling between modal fields is shown to be predominantly reactive in the sapphire-loaded cavity, and can degrade a mode with Q>10⁸ by several orders of magnitude. Interactions between line resonances and T-SLOSC modes are observed to be predominantly resistive through the superconducting niobium probes. Cross-coupling coefficients between some interacting modes have been determined and the reflection coefficients modeled     

Analysis of Dielectric Resonators with Tuning Screw and Supporting Structure

The finite-element method is applied to calculate the resonant frequencies and electromagnetic field distributions of axisymmetric dielectric resonator modes. Analyses of several resonator shapes, including ring resonator, double resonator, and rod resonator with tuning screw and supporting structure, are made.     

Tunable CO2waveguide laser with high transverse mode and line discrimination

A CO2waveguide laser with a special resonator configuration is described. The resonator mirrors with curvature radiiRare located at a distanceR/2from the ends of the waveguide tube. The properties of this resonator, such as transverse mode control and line discrimination, are discussed and measurements concerning the tuning characteristics and the laser output power are presented.     

Voltage-controlled oscillator using dielectric resonator

A simple type of voltage-controlled oscillator using a dielectric resonator is presented for MIC applications, operating at 1.69 GHz. This gives a 0.5% tuning range, for -104 dBc/Hz FM noise     

Dielectric ring-gap resonator for application in MMIC's

A dielectric resonator, the dielectric ring-gap resonator, is introduced and analyzed. The dielectric ring-gap resonator is obtained by sawing a narrow gap into a dielectric resonator. Resonant frequencies and unloaded Q-factors of quasi-TE_0pq mode in the ring-gap resonator have been calculated by an appropriate equivalent circuit starting from the resonant frequencies and the field distributions of the TE_0pq modes in the ring resonator. The calculated resonant frequencies of the fundamental quasi-TE₀₁₁ mode show an accuracy of <1% compared with the experimental results. Coupling techniques to couple the ring-gap resonator to a microstrip line on a thin substrate, using the electric fringing field near the gap, have been experimentally investigated. A rigorous method for determining resonant frequencies and field distributions of TE modes in a multicomposite multilayered cylindrical resonator is presented. This resonator consists of numbers of cylinders that are arbitrarily layered in the axial direction     

S波段低相噪同轴介质压控振荡器设计

运用串联反馈振荡器理论设计了一个工作于S波段的低相噪同轴介质压控振荡器。首先分析了同轴介质谐振器的理论以及串联反馈振荡器的工作原理,然后在高频电磁仿真软件HFSS和ADS中进行仿真和设计。为了实现电调谐,将变容管合理地加入振荡器,最终设计完成了一个S波段的低相噪同轴介质压控振荡器。通过对实物成品的测量和调试表明,此压控振荡器达到了预定的技术指标,各项性能良好。测试结果:工作频率为2.075~2.250 GHz,调谐范围为1.75 GHz,输出功率≥11 dBm,谐波抑制度≥23 dBc,相位噪声优于-133 dBc/Hz@100kHz。     

U-band shield suspended-stripline Gunn DRO and VCO

A millimeter-wave IC dielectric resonator oscillator (DRO) is proposed. Equations that give the resonant frequency of the dielectric resonator DR in suspended stripline (SSL) are derived. A U-band voltage-controlled oscillator (VCO) with varactor tuning also has been developed. The Gunn diode and varactor used in both of the oscillators are commercially available packaged devices. Restrictions on the performance of the oscillators imposed by packaged and mounted networks and the self-characteristics of the solid-state devices have been analyzed. An electronic tuning range greater than 1000 MHz with an output power exceeding 15 dBm across the bandwidth in the 53-GHz region has been realized for the SSL VCO. An SSL DRO with an output power of more than 17 dBm and a mechanical tuning range of 1.5 GHz in the 54-GHz region has been achieved     

Ultralow Temperature Processing and Integration of Dielectric Resonators on Silicon Substrates for System-on-Chip Applications

Ultralow temperature processing of Ba₂Ti₉O₂₀ thin-film ceramics and the attachment of a porous dielectric resonator cylinder on a conducting prepatterned silicon substrate have been accomplished using a hydrothermal process at 150degC/3 h. Enhanced densification and mechanical strength at the bulk ceramic-thin-film interface were induced by a dissolution-crystallization process involving a sol-gel solution under 13-15 atm pressure. Recrystallization forms electrical bridges between powder particles to form an interconnected microstructure, which eliminates grain boundary defects and, hence, improves the dielectric properties. This method has potential for growth of dielectric resonators on integrated circuits for system-on-chip applications and is implemented for the fabrication of an integrated dielectric resonator antenna.     

Broadband U-shaped dielectric resonator antenna with elliptical patch feed

A dielectric resonator antenna formed by a U-shaped dielectric resonator and a conformal elliptical patch feed is proposed for wideband communication applications. Simulated results agree well with measured ones, showing good performance in terms of bandwidth and radiation patterns. The measured impedance bandwidth of S₁₁ < -10 dB is about 72%, covering the frequency range 3.82-8.12 GHz. It has a gain of 4.3-7.6 dBi over the whole operating band with a ground size of about 1.2 lambda₀ times 1.2 lambda₀, lambda₀ being the central operating frequency.