Compact lowpass filter using spiral compact microstrip resonant cells

A novel lowpass filter using spiral compact microstrip resonant cells (SCMRCs) for size reduction is presented. Four SCMRC resonators as open stub lines are connected at both sides of an SCMRC resonator so that the port impedance at the lowpass band is matched to 50 /spl Omega/. The proposed lowpass filter has compact circuit size and wide stop-band. A demonstration lowpass filter is designed, fabricated and measured. It shows low insertion loss, flat response in the lowpass band and wide stop-band.     

A compact coupler design using meandered line compact microstrip resonant cell (MLCMRC) and bended lines

Wireless Networks - In this paper, a novel branch-line coupler using meandered line compact microstrip resonant cell (MLCMRC) and bended lines is proposed. The presented coupler works at...     

Amplifier linearization using compact microstrip resonant cell-theory and experiment

This paper presents a novel technique for reducing the intermodulation distortions (IMDs) in power amplifiers. In this method, both second- and third-harmonic components generated by the transistor are reflected back simultaneously by the compact microstrip resonant cell (CMRC) at the input port with proper phases to mix with the fundamental signal for the reduction of IMDs. A rigorous mathematical analysis on the effectiveness of multiharmonic reflections has been formulated and derived using the Volterra series. Moreover, the delay mismatch factor of the proposed method is analytically studied and the result shows that a better tolerance to the delay error can be achieved by using CMRC circuitry. Standard two-tone test measurements reveal 32- and 22-dB reductions for the third-order IMD and fifth-order IMD, respectively, without affecting the fundamental signal at 2.45 GHz. Meanwhile, the proposed approach gives a peak power added efficiency of 53% with 11.5 dB transducer gain and 15 dBm output power for a single-stage SiGe bipolar junction transistor. The adjacent channel power ratio (ACPR) is -55dBc for a data rate of 384-kb/s quadrature phase shift keyed modulated signal with 2-MHz spanning bandwidth, and this ACPR is maintained for a broad range of output power level.     

Design of a highly PAE class-F power amplifier using front coupled tapered compact microstrip resonant cell

This article presents the design and implementation of a class-F power amplifier (PA) with a low voltage pHEMT, using a novel Front Coupled Tapered Compact Microstrip Resonant Cell (FCTCMRC) for obtaining a high-efficiency performance. The FCTCMRC is used as a harmonic control circuit, which is short and open circuit for the second and third harmonics, respectively. The required dc-supply voltage is low due to application of a low-voltage pHEMT in the circuit implementation. Therefore, the class-F power amplifier is designed with a high power added efficiency (PAE) and compact circuit size. To verify the method, the designed class-F PA is fabricated using a pHEMT at 1.1 GHz. The proposed class-F power amplifier using the FCTCMRC has obtained 86%PAE under 10 dBm input power, which achieves 16% improvement, also, the circuit size including the harmonic control circuit and output matching is decreased about 25%, all in comparison with the designed PA using the conventional CMRC. The measurement results of the fabricated power amplifier are in good agreement with the simulation results, which verifies the proposed design methodology.     

Novel compact circularly polarized square microstrip antenna

A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed     

A novel microstrip ring hybrid incorporating a PBG cell

An experimental investigation of a novel compact microstrip 180° ring hybrid incorporating a one-dimensional (1-D) slow-wave structure, in the form of perforations on the ring itself, is presented. The size of the hybrid is reduced by 23% due to the slow-wave effect, and this size reduction technique has potential applications in MICs and MMICs. The measured insertion loss is comparable to that of a conventional microstrip hybrid     

Novel compact parallel-coupled microstrip bandpass filters with lumped-element K-inverters

Novel compact parallel-coupled microstrip bandpass filters are proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (/spl lambda//4) resonator filters. As a result, the filter order can be doubled without increasing the circuit area, and no repeated passband is observed at twice the center frequency. In addition, by introducing the cross-coupling effect, two transmission zeros at upper and lower stopbands may be created. Simple equivalent-circuit models are also established as effective design tools. Specifically, several compact fourth-order microstrip bandpass filters with good stopband rejection are implemented and carefully examined.     

New compact microstrip antenna

A new microstrip antenna geometry with considerable reduction in size, with similar radiation characteristics to those of an equivalent rectangular patch antenna is proposed. A relationship has been suggested for finding out the resonant frequency of the new geometry, and its validity has been established by the experimental results. Without increasing the aperture area, this geometry also offers a facility for considerably reducing the resonant frequency compared to conventional patches     

Analysis of a new compact microstrip antenna

A new compact microstrip antenna element is analyzed. The analysis can accurately predict the resonant frequency, input impedance, and radiation patterns. The predicted results are compared with experimental results and excellent agreement is observed. These antenna elements are more suitable in applications where limited antenna real estate is available     

Compact and selective lowpass filter with very wide stopband using tapered compact microstrip resonant cells

A novel microstrip lowpass filter is proposed. It consists of a simple tapered structure using periodical compact microstrip resonant cells. Owing to the introduction of the tapered structure, the proposed lowpass filter has successfully addressed simultaneously the problems of compactness, matching, selectivity, insertion loss and the suppression of spurious frequency bands. A demonstration filter has been designed, fabricated and tested to show the validity of the proposed structure.     

Circular resonant structures in microstrip

Mode patterns of circular disc resonant sections are analysed. Radiation losses are expected to be small for the dominant mode, which would therefore have the highest Q value.     

Fully integrated W-band microstrip oscillator

A fully integrated microstrip oscillator is described. The active element is an InP transferred-electron device operating in its fundamental mode of oscillation. For measurement purposes, the oscillator structure is mounted in a test assembly and fitted with a waveguide to microstrip transition. Output powers of 16 mW have been observed at the waveguide output port at frequencies in the range 80 GHz to 83 GHz. Transition and circuit losses are approximately 3 dB indicating a device output power of 32 mW.     

一种便携式微带超宽带天线

改进了一种印刷单极U型微带超宽带天线.利用Ansoft公司的高频仿真软件HFSS对影响其辐射性能的关键参数进行了仿真计算,通过优化使其尺寸减少到原来的22%,阻抗带宽也展宽了24%,最后给出了天线的反射损耗曲线和辐射方向图.天线的-10dB反射损耗的频率覆盖范围为2.3～11.2GHz.这种天线不仅适用于短距离超宽带无线通信,而且也适合于无线局域网(WLAN)与蓝牙(BT)通信.     

Low-loss compact Butler matrix for a microstrip antenna

This paper presents the design and realization of a double four-port Butler matrix to feed a four-column array antenna with two orthogonally polarized signals (to obtain polarization diversity). The main goals of this study are the reduction of the size and the losses of the network. In order to meet those requirements, a bi-layer structure, the suspended stripline, has been adopted to support the circuit. Moreover, the complete network has been integrated in a single unit. The double four-port Butler matrix has been etched on both sides of the suspended substrate to solve the problem of the cross between the lines. The broadside suspended 3-dB directional coupler has been chosen for the design of the 3-dB hybrid coupler. In order to change the side of the suspended substrate, contactless transitions have been used. The network is designed to work within the range of frequencies of the GSM-900-MHz standard: band 880 MHz-960 MHz, center frequency f₀=920 MHz. Measured losses for a 4×4 Butler matrix are 0.3 dB     

Gain-enhanced compact broadband microstrip antenna

With the loading of a high-permittivity superstrate layer and a 1 Ω chip resistor, a compact rectangular microstrip antenna with enhanced gain and wider bandwidth can be implemented. With the antenna size reduced to be ~6% that of a conventional patch antenna, the proposed structure can have an operating bandwidth of more than six times that of a conventional patch antenna, with an almost equal antenna gain level. Details of the experimental results are presented and discussed     

Improved compact microstrip resonance cell lowpass filter with wide stopband characteristics

An improved compact microstrip resonance cell (CMRC) structure is presented. Good lowpass performance and wide stopband characteristics can be achieved with a simple single resonant cell; four transmission zeros are introduced into the stopband and thus out-of-band rejection is significantly improved. Measured results of the fabricated prototype show that the insertion loss is less than 0.1 dB in the whole passband, and stopband bandwidth better than -10 dB is obtained from 2.9 to 15.9 GHz, which is an improvement of 138.3% from a conventional CMRC     

Stabilisation of a W-band microstrip oscillator by a dielectric resonator

The effect of temperature on the performance of a dielectric resonator compensated W-band impatt diode microstrip oscillator is shown to be quite small. The frequency change was about 2 MHz/°C as compared to the uncompensated oscillator's 10 MHz/°C. The design of the oscillator is presented and the resonator used was a cuboid of temperature compensated barium nonatitanate.     

Resonance frequencies of compact microstrip antenna

A simple technique for calculating the resonance frequencies of a compact arrow-shaped microstrip antenna is presented and discussed. The accuracy of the method is validated by experimental results     

Metamaterial-based compact zeroth-order resonant antenna

A metamaterial-based compact one-unit-cell antenna realised on a microstrip line is presented. The size of the proposed antenna is only 6 X 13.5 mm (or 0.05 X 0.13 λ₀) at 2.7 GHz owing to zeroth-order resonance. The design procedures with closed-form solutions are provided using transmission line theory considering radiation loss. The measured antenna bandwidth is 15 MHz and total gain is 1.22 dBi.