Suppression of even modes in microstrip ring resonators

Unwanted even order modes in tunable microstrip ring resonators can be suppressed by providing a low resistance path to ground at an appropriate point on the ring. This suppression method is simple to implement, and has minimal effect on the Q factor and the resonance frequency of the wanted modes     

Complementary split ring resonators for microstrip diplexer design

A new topology for the design of microstrip microwave diplexers, based on the use of quasi-lumped resonators, is presented. Specifically, the receiver (Rx) and transmitter (Tx) filters of the diplexer are implemented by etching complementary split ring resonators (CSRRs) in the ground plane as well as series capacitive gaps and shunt inductive strips in the upper metal level. By this means, narrowband microwave diplexers with transmission zeros can be synthesised, which allow for the improvement of Rx/Tx isolation. A prototype device operative in the 2.4-3.0 GHz frequency band is presented. Measured insertion losses are lower than 2 dB while the isolation between Rx/Tx channels is in the vicinity of 40 dB. Diplexer dimensions (29.8/spl times/16.3 mm), which are small on account of the semi-lumped resonators employed, and performance point to the practical application of these structures in communication transceiver front-ends.     

Miniaturised microstrip bandpass filter using stepped impedance ring resonators

A novel microwave bandpass filter using microstrip stepped impedance ring resonators is reported. The new filter has the advantages of compact size together with sharp rejection of outbands. A two-pole microstrip bandpass filter of this type has been implemented and examined, theoretically and experimentally.     

Design of microstrip highpass filters with complementary split ring resonators

An accurate equivalent circuit model and the parameter extraction method are presented for the microstrip line with a complementary split ring resonator. A highpass filter with steep rejection slope is designed based on the model. Numerical simulation and measurement confirms the efficient analysis and design procedure and the validity of the highpass filter configuration     

Rectangular resonators in inverted microstrip and suspended microstrip

Resonant frequency characteristics of rectangular resonators in a generalized shielded suspended substrate line are analysed using a rigorous spectral domain technique. The computed dominant mode resonant frequency of rectangular resonators in a suspended microstrip with centred dielectric, inverted microstrip and suspended microstrip are presented as a function of various structural parameters. These characteristics are distinct from those obtained for a conventional microstrip rectangular resonator. Experiments are carried out in the frequency range 4-18 GHz to verify the computed resonant frequencies for a suspended microstrip with a centred dielectric using first-order basis functions. The results should find applications in the design of inverted microstrip and suspended microstrip passive microwave and millimetre wave integrated circuits.     

High frequency permittivity determination by spectra simulation and measurement of microstrip ring resonators

The S/sub 21/ spectra of microstrip ring resonators have been measured experimentally and also computed using the finite-difference time-domain (FDTD) method. The dielectric constant of the substrate was determined by fitting the simulation results to the experimental data. The results are more self-consistent than those obtained using the Wheeler-Hammerstad method.     

High Q factor resonators in microstrip

A theoretical estimate has been made of the unloaded Q factor available from half and whole wavelength transmission-line resonators on an Al2O3 substrate. This takes ohmic losses into consideration as well as the radiation losses from various types of cavity termination. It is shown that optimisation of the Q factor of open-circuit terminated resonators demands a critical choice of substrate thickness and line characteristic impedance. Short-circuit terminated cavities generally have a substantially higher Q factor. A measurement technique has been developed, based on lightly coupled transmission probes. This has enabled practical measurements to be made of the unloaded Q factor of various microstrip cavities. Agreement with theory is satisfactory. Q factors up to 600 have been measured.     

Shielded rectangular microstrip disc resonators

A modification of the least-squares method is employed to calculate the resonance frequencies of shielded rectangular microstrip discs. Since the approach is a rigorous one, it includes endeffects and dispersion of the open-ended line, by which the configuration-can be identified. Results are given for quasi-TEM half- and whole-wave resonators and are compared with those obtained by simple line theory.     

Dual band microstrip patch antenna array loaded with split ring resonators and via holes

Reduction in antenna size by using multi-band radiators play a vital role in the miniaturization of present world wireless handheld devices, as dual band behaviour of the antennas result in the integration of more than one communication standard in a single system and thus, saving the installation space required for separate antennas. In this context, this communication presents a shorted-pin dual band metamaterial inspired microstrip patch antenna array. Under the unloaded conditions, the traditional patch antenna array resonates at 5.8 GHz with gain of 9.8 dBi and bandwidth of 540 MHz. However, when each patch of this traditional antenna array is loaded with split ring resonator (SRR) and a metallic via hole is introduced in the patch, the same antenna array produces an additional resonant frequency in IEEE 802.11b/g/n 2.45 GHz Wi-Fi band with bandwidth and gain of 290 MHz and 5.6 dBi, respectively, while the initial resonant frequency (i.e. 5.8 GHz) gets shifted to IEEE 802.11ac 5 GHz Wi-Fi band, providing the gain and bandwidth of 11.4 dBi and 510 MHz, respectively. The proposed antenna array has been fabricated, and the measured results are presented to validate the proposed array. Moreover, the equivalent circuit of the proposed antenna array has been designed and analyzed to validate the simulated, measured and theoretical results. Attainment of dual band characteristics by incorporating the metamaterial with single band traditional patch antenna array makes this structure novel, as this has been achieved without any extra hardware cost, size and loss of structural planarity. Also, both the frequency bands of this proposed metamaterial inspired antenna array possess considerable gain and bandwidth.     

Si基双环谐振腔力敏传感特性研究

为研究双环谐振腔结构力敏传感特性,设计了不同半径比的基于绝缘衬底上硅的双环微腔结构,通过理论分析以及实验测试并结合有限元仿真,得出：半径比为3:1的双环结构的灵敏度为80.26/,而半径比为1:1的双环结构的灵敏度高达128.87 pm/Mpa,具有高的检测灵敏度,表明双环微腔敏感结构单元可应用于应力检测领域。     

Spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators

In this letter, spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators (SRRs) is demonstrated for the first time. By etching SRRs in the upper substrate side, in close proximity to conductor strip, strong magnetic coupling between line and rings arises at the resonant frequency of SRRs. This inhibits signal propagation in the vicinity of that frequency, allowing the rejection of undesired passbands by properly tuning SRRs. To test this novel technique, we have designed and fabricated two different SSRs-based filters. In one case, the rings have been designed to suppress only the first spurious band, and SRRs have been etched at both sides of the 50-/spl Omega/ access lines. For the other prototype, SRRs have been etched on the active device region (i.e., surrounding the parallel coupled lines) and have been tuned to eliminate the first and second undesired bands. The measured frequency responses for these devices confirm the efficiency of this technique to suppress frequency parasitics, with rejection levels near 40 dBs, leaving the passband unaltered. Since SRRs are small particles (with sub-wavelength dimensions at the resonant frequency), this approach does not add extra area to the final layouts. Moreover, the conventional design methodology of the filters holds.     

Mode analysis in microstrip resonators part II

In this contribution, the transmission line model for a printed circuit microstrip resonator is used to theoretically investigate the modes supported by simple structures. Computer analysis yields useful information on the harmonic response of resonators that is relevant to the design of printed antennas and harmonic generators.     

Effective negative-/spl epsiv/ stopband microstrip lines based on complementary split ring resonators

In this letter a super-compact stopband microstrip structure is proposed. The frequency gap is produced by an array of complementary split ring resonators (CSRRs)-a concept proposed here for the first time-etched on the ground plane. This behavior is interpreted as due to the presence of a negative effective dielectric permittivity in the vicinity of resonance. The resulting device produces a deep rejection frequency band with sharp cutoff, and a pass band that exhibits very low losses and good matching. Due to the sub-lambda operation of CSRRs, the electrical size of the device is very small.     

Tunable microstrip resonators with ferroelectric capacitors

The question of increasing the tuning band of microstrip resonators that use ferroelectric capacitors for tuning in the region of increased electric lengths is considered which allows using them in the upper part of the centimeter band (Ku-band, K-band). Band properties of regular and step-irregular resonators operating at the lowest resonant frequency are analyzed.     

Radiation from half-wavelength open-circuit microstrip resonators

Calculations are described for the radiation loss of a half-wavelength open-circuit microstrip resonator, and results are given for a range of microstrip effective relative permittivities. Satisfactory correlation with experimental measurements has been obtained, and the method is believed to give a better estimate of radiation loss for this type of resonator than has formerly been available.     

Magnetostatic wave resonators using microstrip disk

The authors propose a magnetostatic wave resonator using yttrium-iron-garnet (YIG) film with a microstrip disk. Assuming a magnetic wall at the edge of the disk, a dispersion relation is derived and solved numerically to obtain the resonant frequency. Resonant mode charts are given for various parameters of resonator. The quality factor is also given as a function of the resonator dimensions. Resonant characteristics are confirmed experimentally using 40-μm- and 13.5-μm-thick YIG films with 5-mm-diameter strip disk at S band     

MMI-coupled ring resonators in GaInAsP-InP

The characteristic response of single and double GaInAsP-InP ring resonators in the form of race tracks with a radius of 100 and 200 μm are presented. The used multimode interference (MMI) coupler is as short as 150 μm. A contrast of 13 dB, a finesse of six, and free spectral ranges of 50 and 100 GHz have been achieved for the single ring resonator. The double ring resonator has a full-width at half-maximum (FWHM) of 0.25 nm for the throughput port and 0.4 nm for the drop port     

Varactor-tunable uniplanar ring resonators

Slotline and CPW ring resonators are introduced and integrated with varactor diodes to create electronically tunable uniplanar ring resonators. Varactors electronically tune the second resonant mode of the slotline ring over a 23% bandwidth from 3.03 to 3.83 GHz with a 4.5±1.5 dB variation in insertion loss. Similarly, a CPW ring resonator was tuned over a 22% bandwidth from 2.88 to 3.59 GHz. Both resonators offer the ground plane and center conductor on the same side of the substrate to allow easy series or shunt insertion of solid-state devices. DC biasing is naturally integrated in the slotline structure and straightforward in CPW. Monolithic implementation of these resonators would not require via holes to ground solid-state devices which should reduce processing complexity and increase production yields     

Analysis of microstrip resonators of arbitrary shape

A space-domain approach based on a mixed-potential integral equation formulation is developed for efficient computation of complex resonant frequencies of laterally open microstrip-pitch resonators of arbitrary shape. The effects of the substrate-which may consist of any number of planar, possibly uniaxially anisotropic, dielectric layers-are rigorously incorporated in the formulation by means of the vector and scalar potential Green's functions. The current distribution on the conducting patch is approximated in terms of vector basis functions defined over triangular elements. Computed resonant frequencies, quality factors, modal currents, and far-field radiation patterns are presented for several microstrip resonators. For patches of simple, regular shapes, the results are in agreement with published data obtained by specialized techniques, which, unlike the method presented here, are not easily extendible to arbitrary shapes     

Resonance splitting in nonuniform ring resonators

The frequency response of a microstrip ring resonator with small terminal couplings is discussed. For resonators consisting of nonuniform lines, there is shown to be resonance splitting in the transfer function.