紧凑型毫米波功率合成/ 分配器研究*

介绍了两种在传统波导魔T上改进的具有共面臂的波导魔T功率合成/分配器和一种采用电阻膜片 提高端口匹配隔离度的基于模式转换器的径向功率合成/ 分配器,并给出了这些功率合成/ 分配器的特性仿真和测 试结果。这些功率合成/ 分配器均适用于毫米波频段,具有高隔离度、小型化、易加工等特点。     

Design of Low-Profile Millimeter-Wave Substrate Integrated Waveguide Power Divider/Combiner

A low-profile millimeter-wave substrate integrated waveguide (SIW) power divider/combiner is presented in this paper. The simplified model of this compact SIW power dividing/combining structure has been developed. Analysis based on equivalent circuits gives the design formula for perfect power dividing/combining. In order to verify the validity of the design method, a four-way SIW power divider/combiner circuit operating at Ka band is designed, fabricated and measured. Good agreement between simulated and measured results is found for the proposed passive power divider/combiner. Experiments on the four-way passive divider/combiner back-to-back design demonstrate a minimum overall insertion loss of 1.5 dB at 31.1 GHz, corresponding to a power-combining efficiency of 84%. The measured 10-dB return loss bandwidth is demonstrated to be 2.2 GHz, and its 0.5-dB bandwidth was 2 GHz.     

Broadband transition between air-filled waveguide and substrate integrated waveguide

A Ka-band broadband transition between an air-filled waveguide and a substrate integrated waveguide (SIW) is proposed. The transition is realised by using a radial probe inserted into the height-tapered metal waveguide. Results show that an insertion loss less than 2.5 dB and a return loss better than 14 dB in the frequency band 28.3-39.5 GHz are obtained for a back-to-back structure     

Broadband Eight-Way Differential SIW Power Divider with Bandpass-Filtering Response Using Novel Hybrid Multiple-via Probe and Multiple Radial Slots

A broadband eight-way differential substrate integrated waveguide (SIW) power divider with bandpass-filtering response by using novel hybrid multiple-via probe and multiple radial slots has been presented in this paper. The novel hybrid multiple-via probe are employed to achieve broadband impedance matching, while the multiple radial slots are used to improve the out-of-band rejection level. An eight-way differential SIW power divider with bandpass-filtering response is designed, fabricated, and measured. The measured results agree with the simulated ones closely in the desirable frequency range. The measured average insertion loss of the eight-way power divider is approximately 9.3 dB and input return loss is greater than 15 dB from 3.2 to 8.1 GHz. Moreover, the out-of-band rejection band with more than 25 dB attenuation from 9 GHz to more than 11 GHz is observed. A maximum amplitude imbalance of \(\pm 0.7\,\hbox { dB}\) is observed over the entire operating frequency range.     

Ka-Band Four-Way Power Combiner Based on Multi-layer Substrate Integrated Waveguide

A novel millimeter-wave power divider/combiner based on rectangular waveguide to multi-layer substrate integrated waveguide (RWG—MLSIW) transition is proposed in this paper. The input signal can be divided into N way directly by using multi-layer substrate integrated waveguides stacked together and plugged into a normal rectangular waveguide. A four-way multi-layer SIW power combiner operating at Ka-band is designed, fabricated and measured. Good agreement between the experiments and the simulations can be observed, demonstrating 8 GHz bandwidth (from 29 to 37 GHz) with 15-dB input return loss.     

Ka-Band Rectangular-Waveguide Gysel Power Divider with Low Insertion Loss and High Output Isolation

A Ka-band Gysel power divider based on rectangular waveguide is presented in this paper. The model and equivalent circuit of the presented power divider is introduced. The even- and odd-mode analytical method is applied to analyze the equivalent circuit. A Ka-band waveguide Gysel power divider is designed, optimized, fabricated, and measured. Good agreement between the simulated and measured results is demonstrated. The measured average insertion loss is approximately 0.25 dB from 30 to 34 GHz. The measured output isolation in the same frequency band is greater than 15 dB.     

Optimized E-Plane T-Junction Series Power Dividers

A rigorous design theory for compact rectangrdar waveguide power dividers with unsymmetrical series E-plane T-junctions of suitably optimized different waveguide heights and distances is described. The method is based on field expansion in normalized eigenmodes which yield directly the modal S-matrix of two appropriate key building blocks. The immediate modal S-matrix combination of the individual structures includes the effects of all step discontinuities and their mutual higher order mode interaction. Computer-optimized -3.01 dB, -4.77 dB, and -6.02 dB power divider examples achieve about +-0.25 dB coupling deviation at the output ports, together with about 30 dB return loss at the input port, for the chosen design frequencies of 12 GHz, 31.6 GHz, and 15.5 GHz. The -4.77 dB power divider provides a bandwidth of about 8 percent. The theory is verified by measurements.     

V 波段高隔离宽带波导功分器设计

基于电磁场全波分析方法,设计了一种V 波段Y 型结E 面波导功分器,采用多节阶梯阻抗匹配结构实现宽频带;在主传输波导H 面中心插入阻性薄膜的陶瓷基板来提高输出端口隔离度。波导功分器采用硅铝材料制作,具有重量轻、热膨胀系数低、导热良好的优点,与陶瓷基片匹配良好。实测结果表明,在50~60 GHz 频带内,传输损耗优于0. 4 dB,典型隔离度25 dB,两路输出幅度一致性优于0. 19 dB,相位不平衡度优于1. 4°;功率容量理论值可达33 kW。经可靠性试验验证,证明该功分器可靠性高、适合工程使用。     

基片集成波导及其微带过渡的设计

设计了工作于毫米波频段的基片集成波导（SIW）,阐述了基片集成波导及其微带过渡的原理和结构,公式推导出过渡结构中各种参数的计算方法,通过HFSS软件进行仿真,制作了SIW与微带过渡的样品并测试,结果表明在35.5～37.5GHz范围内,波导插损为-1～-2dB,回波损耗小于-10dB,性能良好。     

一种宽带紧凑型基片集成径向波导功分器设计

分别设计了一分四和一分八的宽带紧凑型基片集成径向波导（SIRW ）功分器,通过馈电探针的阶梯化方式,使常规一分四和一分八SIRW功分器在回波损耗小于-15 dB条件下的相对工作带宽由原先的6％和15％分别提高至58％和61％,仿真得到的带内插耗分别在-6．25 dB和-9．25 dB以内。为了验证仿真数据的准确性,对一分四功分器进行了测试,测试结果性能良好,满足工程使用要求。     

一种新型毫米波矩形波导-微带过渡结构

介绍了一种新颖的、适用于毫米波频段的矩形波导-微带过渡电路结构。该过渡电路具有插入损耗低、频带宽、重复性好的特性。其矩形波导E面相对于微带电路面,以及电磁信号传输方向的位置与脊波导-微带过渡相同。该过渡电路的微带线与波导的转换部分采用非接触式结构,并设计了可调节元件,从而在有一定加工误差的条件下改善其产品传输特性。利用高频仿真软件CST,在Ka频段进行了优化仿真,并对利用其优化值所设计的一对背靠背的电路实物进行了测试,在32～40 GHz的频率范围内,插入损耗小于2.36 dB,回波损耗大于7.22 dB;在整个Ka频段内,插入损耗小于3.49 dB。     

220 GHz新型SIW-波导过渡结构的设计

基片集成波导(SIW)既有波导的损耗低、品质因数高、功率容量大的特点,又兼具微带线的低剖面、尺寸小、易于与其他平面电路集成的优点,被广泛应用于微波电路设计之中。鉴于目前测试系统及级联都采用矩形波导端口,为实现对SIW元器件的测试及系统集成,须对SIW元器件进行过渡结构设计。采用三维高频电磁仿真软件仿真和优化,设计了一种新型SIW-波导过渡结构。仿真结果表明：该结构在205~225 GHz频段内,带内插入损耗在0.5~0.6 dB之间,回波损耗大于12 dB;背对背结构,插入损耗小于1.5 dB,回波损耗大于10 dB,相对带宽11.4%。     

A Compact Ka-Band Planar Three-Way Power Divider

A Ka-band planar three-way power divider which uses the coupled line instead of the transmission line is proposed to reduce chip size. The proposed planar topology, different from the conventional Wilkinson power divider, is analyzed and can provide not only compact but also dc block characteristics, which are very suitable for monolithic microwave integrated circuit applications. The divider implemented by a pHEMT process shows an insertion loss less than 5.1 dB and an output isolation better than 17 dB. A return loss less than 18 dB and a phase difference of 4.2deg at 30 GHz can be achieved. Finally, good agreements between the simulation and experimental results are shown.     

Eight-Way Substrate Integrated Waveguide Power Divider With Low Insertion Loss

We describe a compact radial cavity power divider based on the substrate integrated waveguide (SIW) technology in this paper. The equivalent-circuit model is used to analyze the multiport structure, and a design procedure is also established for the structure. An eight-way C-band SIW power divider with low insertion loss is designed, fabricated, and measured. Good agreement between simulated and measured results is found for the pro posed power divider. The measured minimum insertion loss of the eight-way power divider is approximately 0.2 dB and return loss is approximately 30 dB at 5.25 GHz. The measured 15-dB return-loss bandwidth is found to be approximately 500 MHz, and its 1-dB insertion-loss bandwidth is approximately 1.2 GHz. Furthermore, the isolations between the output ports of the eight-way power divider are also discussed.     

W 波段全带宽TE10-TE20模式转换器的研制

新一代W波段慢波结构行波管对波导TE10-TEn0 模式转换器的低损耗、宽带、转换效率等高性能方面提出了要求。 文中重点研究一款全W波段波导模式转换器的设计,实现E 面TE10 输入到H 面TE20 输出的模式转换,并结合高效率转换 结构,给出实际性能验证。首先,分析了波导TEn0 模分布特点,提出E 面功分结构、集成扭波导结构及H 面反相合成等单元 结构;其次,给出TE10-TE20 模式转换整体方案设计与电路优化;最后,结合H 面异相功分结构集成,基于计算机数控技术,实 现该W波段模式转换模块的制备,并完成三端口性能测试。实测结果表明,W 波段全带宽内(75 GHz~110 GHz),该TE10-TE20 模式转换模块输出端口功率分配比为-3.2 dB±0.2 dB,相位差为180°±2°,输入端口回波损耗优于-20 dB,且实测性能 均与仿真结果高度一致,验证了W波段宽带TE10-TE20模式转换器的高效率、低损耗、可行性及鲁棒性。     

A Broadband Substrate Integrated Waveguide (SIW) Planar Balun

A broadband planar balun is presented in this work that makes use of a substrate integrated waveguide (SIW) technique using a printed circuit board process. The proposed balun structure is able to operate at millimeter wave frequencies and it does not require any tight line coupling sections as frequently used in monolithic microwave integrated circuit balun design. In addition, this balun can be integrated with other planar topologies including nonplanar circuits made of the same substrate for achieving high efficiency. This balun structure consists of a 3 dB SIW power divider and microstrip lines that are placed on both sides of the substrate at balanced ports to obtain an 180deg phase shift. The concept is validated by simulations and measurements. Our measured results suggest that a 10 dB return loss at unbalanced port can easily be achieved across a 42% bandwidth from 19 to 29 GHz. Measured amplitude and phase imbalance between two balanced ports are within 1 dB and plusmn5deg, respectively.     

A Compact and Broadband Differential Microstrip Line to Rectangular Waveguide Transition Using Dipole Antenna

In this paper, a compact full Ka-band differential microstrip line (DML) to rectangular waveguide transition is proposed. The dipole antenna with semi-elliptic arms is introduced to transform the differential mode of DML to the TE10 mode of the rectangular waveguide directly. The two arms of the dipole antenna are connected together by a shorting strip to reduce the size of the dipole. Compared with the DML-to-waveguide transition using the fin-line topology, the size of the proposed transition has been reduced by 86 %. To verify this transition, a back-to-back structure is fabricated and tested. It provides a return loss of better than 15.2 dB and an insertion loss of 0.73 to 1.07 dB within a wide frequency range from 26.5 to 40 GHz. The measurement results show good agreement with the simulation results. Furthermore, a tolerance analysis is also performed via the simulation to prove that this transition is robust in the fabrication and mechanical assembly.     

Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm³. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.     

Miniaturized Wilkinson power dividers utilizing capacitive loading

The authors report the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers. Reduction of the transmission line segments from λ/4 to between λ/5 and λ/12 are reported here. The input and output lines at the three ports and the lines comprising the divider itself are coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS), respectively. The 10 GHz power dividers are fabricated on high resistivity silicon (HRS) and alumina wafers. These miniaturized dividers are 74% smaller than conventional Wilkinson power dividers, and have a return loss better than +30 dB and an insertion loss less than 0.55 dB. Design equations and a discussion about the effect of parasitic reactance on the isolation are presented for the first time     

Full Band Millimeter-Wave Power-Combining Amplifier Using a Lossy Power-Combining Network

This paper presents a millimeter-wave broadband power-combining amplifier using a novel lossy waveguide-based power combiner. The lossy combiner has a performance of broadband low-loss combining symmetrically and has properties of good match and high isolation at and between ports, because lossy planar lines are embedded in the lossy combiner and even-mode excitations are weakened. The measured results show that the lossy combiners has a loss of about 0.14 dB and achieves reflection and isolation of about—15 dB in 26.5–40 GHz. And then, using the lossy combiner, a compact lossy waveguide-based four-way-combining network is fabricated. The lossy network has a measured loss of about 0.25 dB and achieves good improvements of match and isolation in the full Ka-band. The improvements can enhance stability of amplifying units when the lossy combining network used in multi-way power-combining amplifier. Using the lossy combining network, a solid-state power-combining amplifier is developed, and corresponding experimental results show that output power is more than 30 dBm and combining efficiency is more than 80 % in the full Ka-band.