一种具有双缝隙结构的双频宽带MIMO天线

设计一种双频宽带多输入多输出(MIMO)天线。天线采用微带线耦合馈电,在天线的表面开有圆环形缝隙,把宽缝隙和窄缝隙结合到一起,因此在辐射体上同时存在2种缝隙结构;天线采用双面结构,带宽范围为1.7~2.33 GHz和3.2~3.9 GHz,2个频带的带宽分别为630 MHz和700 MHz,可用于移动通信的DCS(1 710~1 880 MHz)、PCS(1 850~1 990 MHz)、UMTS(1 920~2 170 MHz)以及WIMAX(3.3~3.6 GHz)。天线在低频段的最大增益为3.6 dB,在高频段的最大增益为5.1 dB,隔离度在-20 dB以下,符合MIMO天线的设计需求。     

Wideband Design of the Fully Integrated Transmitter Front-End With High Power-Added Efficiency

A novel approach to enhance power-added efficiency (PAE) bandwidth and transmitting power bandwidth of the fully integrated transmitter front-end is proposed. To obtain these characteristics, a wideband multifunctional antenna operating as an output matching load of the power transistor and harmonic tuning circuits, as well as a radiator, is designed and fully integrated with a power transistor. Therefore, the wideband direct integration between the output of the power transistor and input of the antenna can be achieved without any impedance transformers. Under the condition of PAE over 50% and transmitting power within 3 dB for the peak transmitting power at the operating band, the measured PAE bandwidth and transmitting power bandwidth are 930 MHz (from 4.9 to 5.83 GHz) and 1030 MHz (from 4.8 to 5.83 GHz), respectively. About a half size is also obtained compared with the conventional wideband class F active antenna for high PAE, and the second and third harmonic radiations of the proposed structure for the normalized peak power of the fundamental frequency are measured less than -30 and -40 dB in all directions, respectively     

TD-SCDMA1.4MHz载波干扰性能分析

本文主要分析了TD-SCDMA 1.4MHz 载波分别与邻近1.4MHz 和1.6MHz 载波共存的干扰性能.通过理论计算,给出了1.4MHz 相对于1.6MHz 带宽时,基站和终端的ACLR 和ACS 射频指标下降程度,并与测试结果进行对比.最后,通过系统级仿真,给出了1.4MHz 和1.6MHz 载波共存时,系统容...     

Traveling-Wave Masers for Radio Astronomy in the Frequency Range 20-40 GHz

Tunable rutile traveling-wave masers (TWM's) have been developed for the frequency ranges 20-25 GHz and 29-35 GHz. Operating data for iron-doped rutile are given and the optimum concentration of iron has been determined. A new type of dielectric image line slow-wave structure (SWS), particularly useful in the frequency range 10-50 GHz, is used in two of the masers. This SWS is found superior to the other structure tested, the dielectrieally loaded waveguide. For both types of masers, a ferromagnetic isolator is used in order to ensure the gain stability of better than /spl plusmn/ 0.2 dB at 30 dB net gain, required for radio astronomical applications. The instantaneous 3dB bandwidth is 30-60 MHz, depending on the maser. The maser package noise temperature at the input waveguide flange was measured to 27 /spl plusmn/ 4 K.     

Elliptical slot loaded partially segmented circular monopole antenna for super wideband application

This article inspects partially segmented circular monopole with elliptical slot for super wideband applications. Two significant characteristics of proposed antenna design are: (i) partially segmented circular monopole, notch loaded elliptical ground plane along with tapered microstrip line provides super wide bandwidth; (ii) elliptical slot in between the partially segmented circular monopole reduces the lower operating frequency (1.07 GHz–0.96 GHz), which in turn enhance the bandwidth dimension ratio (BDR). For verifying the simulated outcomes, antenna prototype is practically constructed and measured. The proposed antenna design attains frequency range from 0.96 GHz to 10.9 GHz (VSWR < 2) with bandwidth ratio of 11.35:1 and percentage bandwidth of 167.22%. Bandwidth dimension ratio of proposed radiator is 6975.22. Frequency as well as time domain analysis of proposed radiator approves its applicability for super wideband wireless applications.     

5G+4G频率及功率协同方案研究

中国移动5G获得2.6GHz及4.9GHz频段共计260MHz的频率资源，其中2.6GHz的160MHz连续带宽，对移动来说既是机遇，又是挑战，如何利用好极为关键。中国移动明确提出“5G+4G”协同组网方案，本文通过测试验证，在4/5G频率及功率协同方面，提出了在240W及320W两种射频设备形态下，4/5G频率及功率的分配建议。     

W波段双带状电子注新型平面慢波结构行波管

提出了一种适用于W波段行波管(TWT)的双注矩形环杆(DBRRB)慢波结构(SWS),该结构具有平面特性,适合于微细加工.在一对T形介质杆的支撑下,RRB SWS适用于双带状电子注工作.利用计算机仿真分析了其高频特性.设计并采用了渐变结构和阶梯波导的宽带输入输出结构.采用粒子(PIC)模拟研究了RRB SWS的热仿真性...     

一种新型宽频多通道（MIMO）天线设计

通过创新性采用两个天线共用一个辐射体的方法,设计了一款双频双极化两通道天线.垂直极化天线采用锥形天线原理,水平极化天线采用半波对称振子原理.通过在宽频锥形辐射体圆形筒上开缝隙的方式,设计得到3个水平极化半波对称振子.仿真结果表明,该天线带宽特性好、单元间隔离度高.垂直极化天线在端口回波损耗小于-10dB的情况下工作带宽为67％.和前人设计的该类型天线相比,本设计弥补了宽频天线仅有一个极化的缺点,垂直极化单元拥有更宽的工作带宽,且两个天线单元的极化方式正交,实现形式简单,结构可靠,成本低廉,有很好的运用前景.另外,通过适当结构参数的调节,也可以使天线工作在其他所需要的频段.     

A 16 element quasi-optical FET oscillator power combining arraywith external injection locking

The authors present analysis, design and experimental results of a 16 element planar oscillator array for quasi-optical power combining. Each element in the array consists of a single FET oscillator with an input port for injection of the locking signal and an output port which is connected to a patch radiator. The array is synchronized using a 16-way power dividing network which distributes the locking signal to the oscillating elements. The array is constructed using a two-sided microstrip configuration, with the oscillators and feed network on one side of a ground plane, and the patch radiators on the opposite side. An effective radiated power (ERP) of 28.2 W CW with an isotropic conversion gain of 9.9 dB was measured at 6 GHz. For an injected power of 10.3 dBm, a locking range of 453 MHz at a center frequency of 6.015 GHz was obtained; a bandwidth of 7.5%. Because of the simple nature of the individual oscillator elements, this approach is well suited to MMIC implementation     

Wideband Propagation Measurements and Channel Implications for Indoor Broadband Wireless Local Area Networks at the 60 GHz Band

This paper addresses some wideband propagation characteristics for Indoor Broadband Wireless LANs at the 60 GHz band. Important system design characteristics from measured results obtained from two wideband 60 GHz LOS radio links are presented. Measurements had been undertaken using the swept frequency channel sounding method. Analysis from the complex frequency responses in a worst-case scenario have yielded to a lower coherence bandwidth value of 5 MHz. Minimum and maximum B_0.9coherence bandwidths obtained with a directional horn transmit and an omnidirectional receive antenna is 1.10 MHz and 105.33 MHz respectively. It has been observed that the coherence bandwidth fluctuates significantly with the location of the receiver with respect to the base station. These results can be used for modelling and design of future Indoor BWLANs.     

Equivalent circuit model-based design and analysis of microstrip line fed electrically small patch antenna for sub-6 GHz 5G applications

In this paper, an equivalent circuit model-based electrically small patch antenna is designed for sub-6 GHz 5G application (3.5 GHz) using 50-Ω microstrip line feed. The overall size of the proposed antenna is 0.33λ₀ × 0.4λ₀ × 0.019λ₀ (28 × 34 × 1.6 mm³) at 3.50 GHz frequency. The proposed antenna has a tilted Y-shape slot, two rectangular shape slots, and two rectangular shape notches in the radiating patch. The proposed antenna is resonating from 3.21 to 3.74 GHz covering the entire sub-6 GHz 5G band (3.3–3.8 GHz). The impedance bandwidth (simulated) of the proposed antenna has been obtained 530 MHz resonating at 3.50 GHz frequency. The good return loss of −23.62 dB is also obtained at 3.50 GHz resonant frequency. The simulation results and geometry of the proposed antenna are validated with equivalent circuit model and experimental measurement of prototype antenna using vector network analyzer (VNA) and anechoic chamber. In the whole operating frequency range, the measured findings show reasonable agreement with the simulated ones. The measured impedance bandwidth of the proposed antenna has been obtained 480 MHz (3.21–3.69 GHz) resonating at 3.48 GHz frequency with a return loss of −21.61 dB, while the theoretical impedance bandwidth of the proposed antenna has been obtained 720 MHz (3.18–3.90 GHz) resonating at 3.58 GHz frequency with a return loss of −21.5 dB. The peak gain of 3.39 (simulated) and 3.2 dB (measured) is obtained at 3.50 GHz frequency. Moreover, the antenna shows 97% (simulated) and 95% (measured) efficiency at 3.50 GHz frequency.     

Slow-Wave Characteristics of a Frame–Rod Structure Based on Micro-Fabricated Technology for THz Vacuum Electron Devices

A simple equivalent circuit analysis of the frame–rod slow-wave structure (SWS) on dielectric substrates of a traveling-wave tube (TWT) is developed, using the quasi-TEM approximation approach for the dispersion and coupling impedance characteristics of the structure. Moreover, the obtained complex dispersion equation and coupling impedance are numerically calculated. The calculation results by our theory method agree well with the results obtained by the 3D EM simulation software HFSS. It is shown that the dispersion of the frame–rod circuit is decreased; the phase velocity is reduced and the bandwidth becomes greater, while the coupling impedance decreases after filling the dielectric materials in the frame–rod SWS. In addition, a comparison of slow-wave characteristics of this structure with a rectangular helix counterpart is made. As a planar slow-wave structure, this structure has potential applications in compact TWTs based on the micro-fabrication technology, which could be scaled to millimeter wave, even to THz frequency.     

New termination for ultrawide-band slot spirals

Slot-spiral antennas utilizing very shallow reflecting cavities have previously been demonstrated by the authors for extremely broadband-conformal applications. We have previously demonstrated the importance of an integrated planar balun and feed for realizing the slot spiral's bandwidth potential. Of equal importance, is the development of a termination that is applicable to the slot radiator. In this paper, we demonstrate a new slot spiral arm termination which, in conjunction with the reflecting cavity and planar infinite balun, allows for very thin yet extremely broadband spirals. The included measurements show that a slot spiral with a diameter of 5.75" and a thickness of merely 0.5" delivers a typical gain of 5 dB_ic from 750 MHz to 4 GHz with good axial ratio performance. Additional loading (both inductive and dielectric) applied to the same spiral can extend its operational bandwidth down to 200 MHz for the same size aperture     

一种应用于三频GPS的宽频带单馈电天线设计

为了实现全球定位系统（global positioning system,GPS）天线小型化并提高其性能,提出了一种新型的三频段GPS宽频带单馈电背腔天线,可在1176.45 MHz（L5）、1227.60 MHz（L2）和1575.42 MHz（L1）三个GPS频段下工作。通过在一端馈送交叉型行波天线并在另一端添加负载,来实现提出天线的右旋圆极化（right-hand circular polarization,RHCP）,且配有弯折线散热器。天线尺寸仅为120×120×29 mm3。仿真和实际测量结果显示,提出的单馈电天线无需使用复杂的馈电网络或双馈结构便可提供宽阻抗带宽（VSWR<2）、低轴比（AR）（<2 dB）和高RHCP增益（>4 dBic）。     

一种中频相同的微波光子信道化接收机

提出一种基于相干光处理的微波信道化接收机,采 用 自由谱范围(FSR)不同的两套光频率梳(OFC,optical frequen cy combs)分别作为 光载波和光本振,使得各个信道的输出具有相同的中频。本文方法将微波信号调制到载波 OFC的每一个 频率分量上,并用法布里-珀罗(F-P)光滤波器对多个信道的调制光边带同时进行带通滤 波,然后与 本振OFC进行相干探测实现频率下转换。若载波OFC比本振OFC的FSR大于1个 信道带宽,并使 F-P滤波器的FSR与本振OFC相等,可得 到等带宽、等中频的微波信道,降低了后续电路的复杂度。对 两个相邻信道进行了实验,将9.74～9.86GHz和9.86～9.98GHz波段的信号分别下转换到两个带宽为120MHz 的中频信道,两个中频信道的中心频率仅相差4MHz分别为900MHz和 896MHz,表明本文方法能够实现等中频的信道输出。     

Programmable Frequency-Hop Synthesizers Based on Chirp Mixing

Frequency-hopped communication equipment require synthesizers capable of providing a large number (N) of discrete frequencies over a wide band. In typical systems N lies in the range of 50 to 10000 and the required bandwidth ranges from 10 to 500 MHz. One technique for implementing a synthesizer is based on mixing chirp signals generated by impulsing SAW filters. Potentially, this method allows fast frequency hop generation over wide bandwidth (<500 MHz) with large numbers of selectable hop frequencies (N< 4000). Furthermore, the hardware can occupy a small volume and dissipate low power compared with conventional synthesizers. This paper examines the techniques and establishes likely parameter and performance bounds. Deleterious mechanisms are identified and their effects on CW spectral purity and fast frequency-hopped link error rate performance is discussed. Experimental results are presented for both a high performance modem, with N equal to 480 across a 96-MHz band and a recent development comprising the basic chirp synthesizer plus phased locked loop (PLL) to provide enhanced slow frequency hop and continuous-wave (CW) spectral purity.     

Electronic mode stirring for reverberation chambers

A modal analysis and a uniform-field approximation are presented for the fields in an idealized two-dimensional, rectangular cavity excited by an electric line source. The model is used to evaluate the effectiveness of frequency stirring, an alternative to mechanical stirring in reverberation chamber immunity measurements. Numerical results indicate that good field uniformity (standard deviation less than 1 dB) can be obtained with a bandwidth of 10 MHz at a center frequency of 4 GHz. The bandwidth requirement is determined primarily by the number of modes excited, and higher frequencies can achieve the same field uniformity with a smaller bandwidth because of the higher mode density. Cavity excitation by two single-frequency sources is also analyzed     

一种新型大带宽高通带平坦度延迟线的设计技术

采用倾斜换能器结构,通过优化设计,研制出中心频率800MHz,带宽200MHz,延迟时间为100ns～3μs且精确可控的声表面波延迟线。该系列产品的插入损耗约为-25dB,直通抑制大于35dB,三次渡越抑制大于50dB,200MHz通带内波纹小于1dB,产品综合性能指标优异。     

基于ADF4111的数字锁相式可调频率源实现

为了在短波接收系统中提供高精度和稳定度的可调本振,采用FPGA与频率综合器ADF4111相结合的方法,产生了范围为70~90 MHz,步进间隔1 MHz的数字锁相式可调频率源,并通过数码管将锁定后的频率值显示出来。重点阐述系统设计方案、硬件实现、主要电路单元设计。最后对本振输出进行测试,结果符合设计指标要求。该方法能根据实际工程需要改变输出信号的频率,步进间隔以及功率,使该类型电路设计能广泛应用于无线通信设备中,为设备的中频和射频电路提供高质量的本振。     

中频带宽对调频遥测非相干解调性能影响分析

遥测地面站设备多采用非相干鉴频解调,设备接收机需要根据码速率来设置中频带宽,中频带宽设置不合理会导致遥测解调误码率增高。为在国军标规定的档数中选出不同码速率的相应最佳中频带宽,文中根据FM信号的解调原理,对非相干鉴频解调方式下,中频带宽对解调误码率性能的影响进行了仿真分析,依据仿真结果提出了最优误码性能下中频带宽参数的推荐值为1.7倍码速率,最后通过硬件实验对仿真分析结果进行了验证。