一种新型宽带圆极化介质谐振器天线设计与实现*

设计了一种宽带圆极化介质谐振器天线,为一种鼠笼形的宽带一分四90毅相移功分微带馈电网络,采用缝隙耦合对介质谐振器顺序旋转耦合馈电。天线结构紧凑、加工简单,仿真和实测结果吻合良好,其阻抗带宽和低于3dB的轴比带宽重叠部分在1.09 GHz-1.83GHz、为50.7%。增益大于3dB 及轴比小于3dB 的波束宽度均达到90°。天线工作频率覆盖四大导航系统,包括中国的北斗系统、美国的GPS 系统、欧洲的伽利略(GALTLEO)系统和俄罗斯的格洛纳斯(GLONASS )系统的频段,天线可应用于全球卫星导航定位系统和无线宽带通信系统中。     

A 22-GHz-band low-noise down-converter for satellite broadcastreceivers

A simple low-cost and high-performance 22 GHz band down-converter developed for a direct-to-home satellite broadcasting system is discussed. The down-converter consists of a low-noise high electron mobility transistor (HEMT) preamplifier, an image recovery mixer with a particular structure using dielectric resonator filters, a 21.4 GHz GaAs FET oscillator stabilized by a dielectric resonator, and an IF amplifier. These components are fully integrating using microwave integrated circuit technology into a small size. A total noise figure of less than 2.8 dB is obtained over the 22.5-23.0 GHz frequency range. The local oscillator achieves a frequency variation of less than 600 kHz_p-p over a temperature range of -20° to +60°C     

Very small control modules with line unified FET configuration forarray processing

Very small, broadband circuit function modules which operate as signal pass switches, phase inverters, and balanced modulators are proposed. They are realized by mutual on/off switching of the FETs in the line-unified FET configuration, with which a main circuit function can be realized in almost the same size as a conventional FET. It is demonstrated that a balanced modulator with a chip size of only 0.6 mm×0.5 mm can control signal gain from 0.7 to -0.7 continuously, while input and output impedances are independent of control bias and isolation is more than 35 dB and up to 18 GHz. These circuit function modules are valuable in constructing miniaturized phase shifters and highly integrated circuits for array processing     

Varactor-Loaded H-Shaped Antenna With Radiation Pattern Control

A varactor-loaded H-shaped antenna with radiation pattern control is described. The antenna has a varactor in each of the four arms. A cylindrical wire model with four varactors is analyzed by the method of moments. The analysis, using the “FEKO” simulator, shows the figure-of-eight radiation pattern is rotated by 360$^{circ}$ in the plane of the antenna with variation of capacitances of the four varactors. An optimum set of capacitances is derived, considering the beamwidth, null level of the radiation pattern, and voltage standing wave ratio (VSWR). A prototype antenna implemented on FR4 substrate has dimensions of 60 mm by 200 mm with a line width of 2 mm. The dc voltages were supplied to the four varactors via the antenna arms where slits were inserted. A 110 $Omega$ feed line and 110 $Omega$-to-50 $Omega$ balun were designed for the minimum VSWR, whilst maintaining good radiation properties. The antenna exhibits rotation of a figure-of-eight radiation pattern with a VSWR less than 2.7, and the maximum gain from ${-}2.9$ dBi to 1.4 dBi at 750 MHz.      

Design and performance of a Ka-band monolithic phase shifterutilizing nonresonant FET switches

This paper describes design consideration and performance of a Ka-band monolithic phase shifter utilizing nonresonant FET switches. The switches show broad-band on/off characteristics up to 60 GHz without using inductors; thus, robust circuit design is possible for a switched-line phase shifter. To determine circuit topology, we introduce a schematic design approach. As a result, desired phase shift as well as good matching characteristics can be realized. The developed 4-bit monolithic phase shifter demonstrates an overall phase deviation less than 5° rms and an insertion loss variation less than 0.65 dB rms from 33 to 35 GHz. For all 16 states, the insertion loss is measured to be 13.1±1.1 dB and the VSWR is less than 1.6. The chip size of the monolithic phase shifter is 2.5 mm×2.2 mm     

Three orthogonal polarisation DRA-monopole ensemble

A dual feed HE/sub 11/spl delta// mode dielectric resonator antenna (DRA) loaded monopole antenna ensemble is described. The two antennas were unaffected by co-location, having coupling less than -25 dB at 2.33 GHz, making the ensemble capable of radiating all three orthogonal linear polarisations. The dielectric resonator antenna had an input impedance bandwidth of 1.9%, while the monopole gave 56%. This small volume ensemble antenna is suitable for mobile communications terminals.     

A stereo multibit ΣΔ DAC with asynchronous master-clockinterface

A two-channel multibit ΣΔ audio digital-to-analog converter (DAC) with on-chip digital phase-locked loop and sample-rate converter is described. The circuit requires no over-sampled synchronous clocks to operate and rejects input sample clock jitter above 16 Hz at 6 dB/octave. A second-order modulator with a multibit quantizer, switched-capacitor (SC) DAC, and single-ended second-order SC filter provides a measured out-of-band noise of -63 dBr with less than 0.1° phase nonlinearity. Measured S/(THD+N) of the DAC channel including a 0-63 dB, 1 dB/step attenuator is greater than 90 dB unweighted. The circuit is implemented in 0.6-μm DPDM CMOS, dissipating 220 mW at 5 V. Die size is 3 mm×4 mm     

Wideband Circularly Polarized Dielectric Resonator Antenna

A circularly polarized quadruple strip feed cylindrical dielectric resonator antenna utilizing a pair of 90deg hybrid couplers is investigated experimentally. The antenna is shown to deliver an impedance bandwidth (S₁₁ < -10 dB) of 34.5%, from 1.75 to 2.48 GHz, and an axial-ratio bandwidth (AR < 3 dB) of 25.9%, from 1.65 to 2.14 GHz. The gain and radiation patterns are found to be stable within the passband.     

Circular Polarization Dielectric Resonator Antenna Excited by Single Loop Feed

A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (TE^x_δ11, TE^y_1δ1,) of the rectangular DRA are excited by a 90° phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right‐hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for S₁₁相似文献   

一种新型介质谐振天线设计

采用双层磁电复合材料为基板,制作了一款小型(38 mm×38 mm)宽带介质谐振天线。为减小尺寸并提高带宽,天线采用了共面波导馈电及倒L形金属片加载。通过理论分析,给出了天线的等效电路,并对其进行了仿真分析。结果表明:在回波损耗S11<–10 dB时,该天线的工作频段为4.93~6.75 GHz,实现了宽频带的设计目的。     

Efficiency of 76-GHz post-wall waveguide-fed parallel-plate slotarrays

We design and fabricate various sizes of 76-GHz post-wall waveguide-fed parallel-plate slot arrays. The post-wall waveguide is an array of metalized via-holes with a narrow spacing in a grounded dielectric substrate. The antenna can be easily made at low cost by conventional PCB (printed circuit board) fabrication techniques such as via-holing, metal plating, and etching. We have obtained 40-50% efficiency for various sizes from 26 mm×24 mm to 104 mm×100 mm. We have measured 35.3 dBi gain with 39.3% efficiency at 77.0 GHz in an antenna sized 104 mm×100 mm     

Combination dielectric resonator, power combiner, and antenna

A rectangular dielectric resonator housed in a cutoff parallel-plate waveguide is used both as a radiating element and microwave power combiner. The resonator is excited by using tuned electrically short monopole antennas to induce a longitudinal electric operating mode. The resonator is then used in conjunction with free-running oscillators in order to provide, via mutual injection locking, stable in-phase power combining. Furthermore, the resonator is arranged such that one of its faces radiates a portion of the power-combined signal. Since the resonator is housed in a cutoff waveguide, the cross-polarization radiation from the antenna is suppressed. It was found that, for a single element, a gain in the azimuthal plane of 5 dB could be achieved and, for a two-element array, a gain of 7 dB was obtained with better than -25-dB cross polarization for each case. The oscillator power-combining efficiency for a single-element antenna (two oscillators) was 91%, and the spatial power-combining efficiency for a two-element antenna array, (four oscillators) was found to be 90%. In addition, it is shown that the presence of the dielectric inserts in conjunction with coupled oscillator dynamics provides moderate overall oscillator phase noise improvement     

Transmitter Architectures Based on Near-Field Direct Antenna Modulation

A near-field direct antenna modulation (NFDAM) technique is introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. Near-field direct antenna modulation (NFDAM) can be performed by using either switches or varactors. Two fully-integrated proof-of-concept NFDAM transmitters operating at 60 GHz using switches and varactors are demonstrated in silicon proving the feasibility of this approach.      

一种宽频带介质谐振器天线的设计与实现

摘 要：带宽拓展,一直以来是介质谐振器天线研究重要内容之一。基于此,本文设计了一款宽频带介质谐振器天线。采用共面波导馈电的单极天线与介质谐振器天线的混合结构,通过调节谐振器尺寸和共面波导的结构,使各个工作模式的频带互相重叠,展宽所设计天线的带宽;同时地板上引入开槽技术,对馈线进行阻抗匹配。利用仿真软件对天线参数进行优化仿真,实现天线频带宽度为2.98-7.18GHz（S11<-10dB）,相对带宽达到84.3%,带内最大增益达到4.9dBi。对该天线进行加工测试,仿真与测试基本吻合,结果表明,该天线不仅可实现宽频带,且结构简单,尺寸小,易集成,可广泛应用于WLAN/WIMAX等通信领域。     

A 26-GHz High-Performance MIC Transmitter/Receiver for Digital Radio Subscriber Systems

A high-performance 26-GHz microwave integrated circuit (MIC) transmitter/receiver using frequency-shift-keying (FSK) modulation has been developed. All RF components are fabricated using MIC technology and integrated into a single compact module. Newly developed MIC components include an FSK modulator, a time division multiple access (TDMA) switch, and a single-balanced mixer. The FSK modulator is composed of an IMPATT diode, a varactor diode, and a dielectric resonator. A high-frequency stability of 50 ppm is obtained in the tempera-ture range of -10-45°C. The configuration and performance of the TDMA switch with a high ON/OFF ratio and a low insertion loss are described, A transmitting power of 21 dBm and a receiving noise figure of 8.7 dB are obtained. The bit error rate is measured to evaluate the overall transmitter/receiver performance. The required carrier-to-noise ratio (CNR) has been considerably improved by adopting FSK modulation and by using the MIC transmitter/receiver described in this paper.     

Small eletric monopole mode dielectric resonator antenna

A novel dielectric resonator (DR) antenna is reported. The lowest order mode of the proposed antenna radiates like an electric monopole. The dimensions of the antenna are much smaller than a previously reported structure radiating in a similar mode, e.g. for an antenna fabricated out of ε_r=20 material, the diameter and height of the DR are ~0.08 λ₀ each     

基于介质片加载实现MIMO介质谐振器天线解耦

提出了一种通过在介质谐振器(DR)上表面侧边加载介质片(DS)来实现1×2 MIMO介质谐振器天线(DRA)解耦的新方法。1×2 MIMO DRA采用双层介质基板结构以优化阻抗匹配特性和辐射特性,两DR的边到边间距为0,天线工作在毫米波频段。所加载的DS使得DR内的场重新分布并向DS加载区域以及DS内集中,从而减弱耦合到另一DR单元的场强以实现解耦效果。基于ANSYS HFSS的仿真结果表明天线的-10 dB阻抗匹配带宽为25.6%(22.75～29.43 GHz),带内最大实现了30 dB的隔离度的增强。     

Bandwidth Enhancement of Circularly Polarized Dielectric Resonator Antenna

Axial‐ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband 90° shifter, delivers good characteristics in terms of 3 dB power splitting and consistent 90° (±5°) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR) ≤ 2, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.     

Hybrid high temperature superconductor/GaAs 10 GHz microwaveoscillator: temperature and bias effects

Hybrid YBa₂Cu₃O_7-x superconductor/GaAs microwave oscillators have been designed, fabricated and characterized. The planar oscillators were built on a single 10 mm×10 mm LaAlO₃ substrate. The active elements in the hybrid oscillators were GaAs MESFETs. A ring resonator was used to select and stabilize the frequency. A superconducting ring resonator had a loaded Q at 77 Kg which was 8 times larger than the loaded Q of a ring resonator fabricated out of copper. S-parameters of the GaAs FET were measured at cryogenic temperatures and used to design the oscillator which had a reflection mode configuration. The transmission lines, RF chokes and bias lines were all fabricated from YBa₂Cu₃ O_7-x superconducting thin films. The performance of the oscillators was measured as a function of temperature. The rate of change of the frequency as a function of temperature was smaller for an oscillator patterned from a pulsed laser deposited film than for an oscillator patterned from a sputtered film. As a function of bias at 77 K, the best circuit had an output power of 11.5 dBm and a maximum efficiency of 11.7% The power of the second harmonic was 25 dB to 35 dB below that of the fundamental, for every circuit. At 77 K, the best phase noise of the superconducting oscillators was 68 dBc/Hz at an offset frequency of 10 kHz and less than -93 dBc/Hz at an offset frequency of 100 kHz. At an offset frequency of 10 kHz, the superconducting oscillator had 12 dB less phase noise than the copper oscillator at 77 K     

A Compact 60-GHz Transmitter--Receiver

A new, compact, low-cost, and reliable 60-GHz transmitier-receiver was developed for civilian use. Common components are used for transmitting and receiving functions. An IMPATT oscillator generates the millimeter-wave output power for both the transmitter and the receiver local oscillator. A common antenna is also used for transmitting and receiving signals without a circulator. A mixer is used as a modulator in transmission as well as a receiver front end. A noise figure of 13 dB is obtained by a balanced mixer with a 200-MHz IF frequency differential preamplifier. A reliable packaged GaAs varactor diode is used for the mixer-modulator (MM).