Graphical design of millimeter-wave finline bandpass filters

A very simple yet accurate design procedure for the finline bandpass filters at millimeter wavelengths is presented. The technique enables the geometry of finline bandpass filters to be obtained accurately from simple closed-form equations and curves. Using this graphical approach, various millimeter-wave finline bandpass filters have been designed. Results in V-band (50 to 75 GHz) and W-band (75 to 110 GHz) are presented and indicate a good agreement between the calculated and measured performances.     

A quasi-planar FET amplifier in integrated finline and microstriptechnique

The design and performance of a single-stage 20-GHz GaAs FET amplifier in a quasi-planar technology are described. The component includes a compact, wideband transition between the finline input and output ports and the microstrip impedance-matching networks for the transistor. By virtue of a novel bias network which includes a microstrip bandstop filter and a 50-Ω resistor, this transition provides unconditional stability even at frequencies below cutoff of the finline ports. The overall amplifier has a gain of 6 dB at 20 GHz, and a 3-dB bandwidth of 17%     

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.     

Multifunctional microstrip transmission lines integrated with defected ground structure for RF front-end application

This paper presents multifunctional microstrip transmission lines for designing a high port-isolation dual-frequency orthogonally polarized rectangular patch antenna and the antenna-integrated power amplifier. The proposed lines were realized through the integration of defected ground structures (DGSs) with conventional microstrip lines. A spiral-shaped DGS-integrated microstrip line enhances the port isolation of the antenna, while feeding the 2.0-GHz excitation to the antenna and filtering out the 2.5-GHz receiving signal from the other port. High-order harmonic signal suppression of the power amplifier at the 2.5-GHz port was accomplished by the dumbbell-shaped DGS, thereby improving the efficiency of the amplifier. Measurements show an improvement of 20 dB in port isolation and 3% in power-added efficiency relative to an identical RF front-end, but integrated with a conventional patch antenna. An image impedance of the DGS-integrated microstrip lines can be controlled by the integrated DGS geometries. Relatively high-impedances lines, i.e., 150 and 100 /spl Omega/, are effectively implemented using microstrip lines with 75- and 50-/spl Omega/ linewidths by incorporating the spiral- and dumbbell-shaped DGSs, respectively.     

基于微带无源电路的宽带毫米波分谐波混频器

设计了一款基于微带结构的宽带毫米波分谐波混频器.混频器中引入了短路结构的宽带射频滤波器以及一个高性能本振-中频双工器,这些无源电路能够抑制空闲组合频率,同时为中频、射频以及本振信号提供合适的回路.测试结果表明,本文设计的毫米波分谐波混频器射频工作频率为27～48 GHz,中频工作频率宽至6 GHz.在整个工作频段内上、...     

Characteristic impedances of microstrip and finline with uniaxialor biaxial anisotropic substrates

Spectral domain analysis (SDA) is extended to compute the frequency dependent characteristic impedance Z(f) of boxed microstrip and unilateral or bilateral finlines, printed on biaxial anisotropic dielectric substrates. The most usual impedance definitions have been used     

A 5-GHz highly integrated receiver front-end

In this paper a radio front-end for a IEEE 802.11a and HIPERLAN2 sliding-IF receiver is presented. The circuit, implemented in a low-cost 46-GHz-f _T silicon bipolar process, includes a variable-gain low noise amplifier and a double-balanced mixer. Thanks to monolithic LC filters and on-chip single-ended-to-differential conversion of the RF signal, the proposed solution does not require the expensive image rejection filter and an external input balun. The receiver front-end exhibits a 4.3-dB noise figure and a power gain of 21 dB, providing an image rejection ratio higher than 50 dB. By using a 1-bit gain control, it achieves an input 1-dB compression point of −11 dBm, while drawing only 22 mA from a 3-V supply voltage.     

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     

Microwave and millimeter-wave integrated circuits

This historical review is divided into three sections: microwave integrated circuits (MICs), monolithic microwave integrated circuits (MMICs), and MIC and millimeter-wave integrated-circuit applications     

一种小型半U型缝折叠超宽带微带天线

提出了一种四分之一波长半U型缝隙折叠超宽带微带天线。该天线采用短路面加载半U型缝隙以及折叠辐射贴片的方法,实现了小型超宽带特性;天线的尺寸为18mm×7.5 mm×7mm,相对波长尺寸为0.231λg×0.096λg×0.09λg(λg是天线带宽最低频率对应的介质中波长)。仿真显示,天线的阻抗带宽为39.3%,仿真辐射方向图稳定,平均增益4.3 dB。由矢量网络适量分析仪E5071C实测天线模型,天线的带宽为3.86～6.47 GHz,相对带宽为50.53%,并且从3.53 GHz到大于8.5 GHz频段上电压驻波比小于3,相对带宽超过82.6%。     

A compact branch-line coupler using discontinuous microstrip lines

We introduce a branch-line coupler using discontinuous microstrip lines whose size is significantly reduced relative to the standard design. We manipulate the reactive characteristics of discontinuities in its microstrip lines to achieve a physical size reduction of almost 60% with comparable performance.     

A compact circularly polarized subdivided microstrip patch antenna

A compact circularly polarized subdivided microstrip patch antenna is proposed. The antenna is composed of the interconnection of four corner patches alternating with four strips and a fifth central patch. It presents the very small size of 0.28λ_g by 0.28λ_g at resonance (5.85 GHz), which represents a surface reduction of 60% compared with a conventional microstrip square patch antenna. The proposed antenna exhibits a gain of 4.3 dBi to 5 dBi and an axial ratio lower than 1.8 dB in the range of its bandwidth, which is of 30 MHz     

A highly integrated analog front-end for 3G

This paper describes a reconfigurable analog front-end (AFE) and audio codec IC supporting the wideband code division multiple access (WCDMA) standard. The chip is fabricated on Intel's 0.18-/spl mu/m (SOC) flash+logic+analog (FLA) process technology using a 0.35-/spl mu/m feature size analog transistor. The transmit path contains a 10-bit segmented rail-to-rail digital-to-analog converter, automatically tunable active RC filter, and programmable gain amplifier (PGA) with self-tuning gain and offset correction circuit. The receive path incorporates a PGA, active RC filter, and an 8-bit analog-to-digital converter with built-in offset correction. The AFE operates at 2.7 V with a current consumption of 55 mA and total active area of 15 mm/sup 2/.     

A compact 24 GHz quadrature Doppler radar with front-end MMIC

A compact 24?GHz quadrature Doppler radar front-end monolithic microwave integrated circuit (MMIC) with Tx leakage canceller is developed. The chip is 3?×?2?mm² and the front-end module is 3?×?3?cm². The MMIC consists of a 24?GHz voltage-controlled oscillator, a Tx leakage canceller and two mixers. The radar module can measure speeds as low as 2.5?mm/s, which corresponds to a 0.41?Hz Doppler shift. The quadrature topology enables the signs of a Doppler shift to be detected and obviates the null point problems.     

Stub-tuned microstrip bandpass filters for millimeter-wave diplexer design

This letter presents a new design for microstrip bandpass filters and its application to a millimeter-wave diplexer. Basically, parallel-coupled microstrip lines are utilized for bandpass response and non-uniform open-circuited stubs are added to tune the bandwidth of the passband and improve out-of-band rejection. The designed filters are connected to make a diplexer, which can be used in a phased-array transceiver system operating in millimeter-wave range. The diplexer is designed to separate an input signal containing both 32GHz and 35GHz into two signals of 32GHz and 35GHz, respectively or to combine two signals at 32GHz and 35GHz into one signal.     

Equivalent relative permittivity and unloaded Q factor of integrated finline

To experimentally demonstrate the capabilities of integrated finline, a cavity test fixture was constructed and tested. The results were analysed to determine the manner in which the guide wavelength and unloaded Q factor varied. The measured unloaded Q factor of integrated finline was found to be two to three times better than that of microstrip. Owing to the low loss of integrated finline, its freedom from tight tolerances and compatibility with hybrid devices, this new transmission line is well suited to millimetre integrated circuits.     

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     

Monolithically integrated InP-based front-end photoreceivers

The performance characteristics of a monolithically integrated front-end photoreceiver, consisting of a photodiode and a MODFET amplifier, were analyzed and measured. A vertical scheme of integration was initially used to realize a photoreceiver circuit on InP consisting of an InGaAs p-i-n diode, an InGaAs/InAlAs pseudomorphic MODFET, and passive circuit elements. The device structures were grown by single-step molecular beam epitaxy with an isolating layer in between. The microwave performance of 1-μm-gate MODFETs in the circuit is characterized by f_T=9 GHz, although identical discrete devices have f_T=30-35 GHz. The degradation is due to additional parasitic capacitances present in this integration scheme. In spite of this disadvantage the bandwidth of the circuit is 2.1 GHz. Integration of the p-i-n diode with 1.0- and 0.25-μm-gate MODFETs has also been done in a planar scheme using regrowth, and receiver bandwidths of 6.5 GHz were measured. This value is comparable to that of hybrid circuits with InP-based devices     

A compact high gain microstrip antenna for wireless applications

In this article, we describe a novel type of defective ground surface (DGS) microstrip antenna that achieves higher gain, multi resonant frequency with compact size. The proposed antenna consists of a hexagonal shaped patch with small volume. Six triangular slots have been cut on the ground plane, just below the six corners of the hexagonal radiating patch. Antenna is circularly polarized one and it has the measured peak gain of 7.2 dBi. The antenna shows multi frequency behavior and more than 57% compactness compare to the conventional hexagonal patch antenna. The simulated results are confirmed experimentally. The proposed antenna is simple in structure compared with the regular stacked or coplanar parasitic patch antennas. It is highly suitable for wireless communications.     

A 900-MHz RF front-end with integrated discrete-time filtering

Discrete-time analog filters, rather than off-chip components, have been used to perform frequency selection and down conversion in the integrated front-end for a 900-MHz RF receiver. The first stage of frequency down conversion is implemented with a subsampling switched-capacitor sample-and-hold circuit clocked at 78 MHz. Subsequent stages of discrete-time filtering are realized using switched-capacitor biquadratic filters. An experimental prototype of the front-end had been integrated in a 0.6-μm BiCMOS technology. The circuit provides a system gain of 36 dB and 32 dB suppression of interfering channels over a 40 MHz bandwidth. Referred to the system input, the third-order intercept-point is -16 dBm, and the spot input-referred noise is -82 dBm over a 30 kHz bandwidth. The experimental circuit dissipates 90 mW from a 3.3-V supply and occupies an active area of 1.9×1.9 mm²