共查询到20条相似文献,搜索用时 15 毫秒
1.
Takafumi Kojima Kouichi Kuroiwa Yoshinori Uzawa Matthias Kroug Masanori Takeda Yasunori Fujii Keiko Kaneko Akihira Miyachi Zhen Wang Hideo Ogawa 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(11):1321-1330
We have developed a low-noise heterodyne waveguide Superconductor-Insulator-Superconductor (SIS) mixer with a novel local
oscillator (LO) injection scheme for the Atacama Large Millimeter/submillimeter Array (ALMA) band 10, over the frequency range
0.78–0.95 THz. The SIS mixer uses radio frequency (RF) and LO receiving horns separately and a waveguide 10 dB LO coupler
integrated in the mixer block. The insertion loss of the waveguide and coupling factor of the coupler were evaluated at terahertz
frequencies at both room and cryogenic temperatures. The double-sideband (DSB) receiver noise temperatures were below 330 K
(7.5hf/k
B) at LO frequencies in the range 0.801–0.945 THz. The minimum temperature was 221 K at 0.873 THz over the intermediate frequency
range of 4–12 GHz at an operating temperature of 4 K. This waveguide heterodyne SIS mixer exhibits great potential for practical
applications, such as high-frequency receivers of the ALMA. 相似文献
2.
《Microwave Theory and Techniques》1979,27(3):227-232
Inexpensive glow discharge indicator lamps mounted in a waveguide mount are investgated as mixers at relatively high X-band Iocal oscillator (LO) power levels. The IF conversion efficiency was found to drop off for LO power levels greater than about 30-40 mW, although no damage occurs to the lamps at higher power levels. Because of the small lamp size relative to waveguide cross section, sensitivity is much less than in the free space configuration. For many reasons the use of such devices as mixers should be much more promising at millimeter-wave frequencies than at microwave frequencies. 相似文献
3.
Y. Uzawa M. Takeda A. Kawakami Z. Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(10):1749-1757
A novel broadband tuning circuit composed of two low-current-density half-wave NbN/MgO/NbN tunnel junctions connected by a half-wave NbN/MgO/NbN microstrip line has been successfully tested in a quasi-optical mixer at frequencies above 700 GHz. The circuit had a designed center frequency of 870 GHz, was integrated in a center-fed twin-slot antenna, and was fed via a quarter-wave impedance transformer. Heterodyne measurments showed double-side-band receiver noise temperatures equivalent to 6-9 quanta from 675 to 810 GHz for a mixer with a current density of 6.7 kA/cm2. The RF bandwidth was broader than that of a conventional mixer using a full-wave junction with the same current density. 相似文献
4.
《Microwave Theory and Techniques》1987,35(4):435-440
We have made a systematic experimental study of the performance of millimeter-wave quasiparticle heterodyne mixers which use arrays of SIS tunnel junctions. Sets of arrays with N =1, 5, 10, 25, and 50 junctions in series were fabricated by photolithography. All of the arrays in a given set were made on a single silicon wafer so that their response time parameter omega/sub S/R/sub N/C would be the same. Junction areas were scaled so that the total impedance was the same for each array in a set. Sets of arrays from four wafers with values of omega/sub S/R/sub N/C ranging from 2.6 to 13 were evaluated in mixers at 33 and 36 GHz. These measurements showed that the signal power required to saturate the mixers varies as N/sup 2/ and that the conversion efficiency is nearly independent of N for all values of omega/sub S/R/sub N/C. The mixer noise temperature is independent of N for large values of omega/sub S/R/sub N/C. Therefore, the dynamic range of an SIS quasiparticle mixer can increase in proportion to N/sup 2/. For small values of as omega/sub S/R/sub N/C, however, the mixer noise increases systematically with N. This correlation suggests that the junction capacitance affects the coupling between junctions that can contribute to the noise. 相似文献
5.
W. L. Shan S. C. Shi E. H. Zhao Q. H. Cheng S. Z. Yang P. H. Wu 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(6):921-929
The performance of superconductor-insulator-superconductor (SIS) sub-harmonic mixers is thoroughly investigated in this paper. On account of the importance of the harmonic effect, a full five-port model combined with an enhanced Newton solution is applied to calculate the local oscillator (LO) waveform. The mixer performance is studied as functions of principal parameters including the embedding admittances, LO power and bias voltage. The results are compared with those from the quasi five-port model. 相似文献
6.
A novel circuit architecture for high performance of high-order subharmonic (SH) mixers is proposed in this paper. According to the specified harmonic mixing order, one or more mixer diodes sub-arrays and corresponding power divider as well as phase shift network for RF and LO signals are arranged in the circuit. This proposed SH mixer circuit has improved conversion loss, wide dynamic range and high port isolation for high-order SH mixers. By phase cancellation of idle frequencies, the proposed SH mixer circuit can eliminate complicated design procedure of idle frequency circuits; by phase cancellation of leakage LO power to RF and IF port, and leakage RF power to LO port, the mixer circuit can get high port isolation in LO-IF/RF and RF-LO. The increased antiparallel diode pairs in each sub-array will also lead to well performance by lowering effective series resistance. The proposed SH mixer circuit can be easily realized with power divider and phase shift network for RF and LO signals. 相似文献
7.
8.
《Advanced Packaging, IEEE Transactions on》2009,32(4):773-779
9.
《Microwave Theory and Techniques》1986,34(1):110-119
In this paper, a numerical method is presented for analyzing microwave mixers. Particular consideration is given to the solution of the nonlinear pumping problem of real Schottky-barrier diodes. The new technique has a significantly improved convergence rate, which is demonstrated by means of direct comparisons with other methods. A convergence test procedure is proposed and applied which uses randomly generated harmonic impedances. The proposed numerical technique for solving the nonlinear and linear problem is extended to the analysis of balanced mixers. Fabricated planar balanced mixers are analyzed, both theoretically and experimentally, in a separate paper. 相似文献
10.
Ho Suk Kang Sang Geun Lee Chul Soon Park 《Microwave and Wireless Components Letters, IEEE》2007,17(11):799-801
We propose a single-stacked CMOS mixer that can operate at low local oscillator (LO) power condition with a new switching mechanism. Gating the body terminal makes it possible for the mixer to operate in a more ideal switching mode by utilizing the body effect. Biasing at near pinch-off region gives rise to beneficial aspect, low power dissipation. This circuit is composed of all PMOS transistors which draw only 0.275 mA from a supply voltage of 1.8 V. This circuit features gain and noise enhancement characteristic, low power consumption, and simple topology. The proposed mixer achieves conversion gain of 18 dB, noise figure of 9.1 dB with 0 dBm LO power, and power consumption as low as 0.5 mW. 相似文献
11.
本文首先建立了微波混频器件的频域计算模型,以及相应的频域谱平衡迭代算法,然后对多频信号激励下的微波混频器进行了分析,以此研究了混频器的频率变换特性。 相似文献
12.
13.
Che-Chung Kuo Chun-Lin Kuo Che-Jia Kuo Maas S.A. Huei Wang 《Microwave Theory and Techniques》2008,56(4):793-802
In this paper, three monolithic star mixers using a new miniature dual balun are proposed. The first one is a double spiral transformer mixer, and the second one is a trifilar transformer mixer. Both of these are fabricated using a commercial GaAs pseudomorphic HEMT process. The third is a 3-D transformer mixer, which is fabricated using a commercial CMOS process. These mixers exhibit bandwidths over 25-45 GHz (57%) with local oscillator isolations better than 20 dB. These star mixers are smaller than (lambda/6timeslambda/6) for the mixer core area. Compared with traditional star mixers, these mixers demonstrate 80% size reduction, and achieve good performance with the smallest chip size among all star mixers using monolithic microwave integrated circuit processes. 相似文献
14.
This paper proposes a novel circuit topology for a three-phase power factor correction (PFC) rectifier using a harmonics current injection method. In consideration of lower cost, the harmonics injection method is more suitable than a conventional six-arm pulse width modulation (PWM) rectifier. The harmonics injection current is simply generated by only one switching leg. As a result, the proposed circuit has the advantage of only two switches. An optimal injection current is achieved in order to obtain an input current of sinusoidal waveforms. This paper discusses the basic operation and optimal design method for the proposed circuit. In addition, the validity of the proposed circuit is confirmed by simulation and experimental results. An input current of almost sinusoidal waveform was obtained and an input current total harmonic distortion (THD) of 8.5% was obtained at a load of approximately 1 kW. 相似文献
15.
Alonso J.M. Ordiz C. Dalla Costa M.A. 《Industrial Electronics, IEEE Transactions on》2008,55(3):1085-1089
In this paper, a new control strategy that allows zero-voltage-switching (ZVS) operation of power converters using piezoelectric transformers (PTs) is proposed. The control circuit operates in a closed loop by measuring the phase between the PTs resonant current and the switching pattern and adjusting the switching frequency to the optimum value so that ZVS operation is assured. An innovative nonlinear regulator based on an analog multiplexer is presented. The regulator automatically swaps the signs of the sensed signal and the reference signal to allow generation of the adequate control action. A laboratory prototype for a 6 W resonant inverter was tested; obtained experimental results are also shown. 相似文献
16.
设计了一种可工作于0.9 V低电压和-5 dBm本振功率的CMOS有源混频器.通过在MOS管栅极和衬底间引入耦合电容,利用衬底效应加快MOS管的导通和截止,使开关对的开关状态更理想,有效地降低混频器的噪声并提高其线性特性.采用0.18 μm CMOS工艺设计,在2.45 GHz本振信号和2.44 GHz射频信号输入下,实验结果表明该混频器可有效地实现混频且具有较好的性能指标:电压转换增益为12.4 dB,输入三阶截断点为-0.6 dBm,输入1dB压缩点为-3.4 dBm,单边带噪声系数为12 dB. 相似文献
17.
18.
NING Ning WU Shuang-yi WANG Xiang-zhan YANG Mo-hua 《中国电子科技》2007,5(1):75-80
The effects of stage numbers on power dissipation of pipeline analog-to-digital converter (ADC) are studied and a novel design method aiming for power optimization is presented. In this method, a minimum comparator number algorithm (MCNA) is first introduced, and then the optimum distribution of resolutions through pipeline ADC stages is deduced by MCNA. Based on the optimum stage-resolution distribution, an optimization method is established, which examines the precise function between ADC power and stage resolutions with a parameter of power ratio (Rp). For 10-bit pipeline ADC with scaling down technology, the simulation results by using MATLAB CAD tools show that an eight-stage topology with 1-bit RSD correction achieves the power optimization indicated by the power reduction ratio. 相似文献
19.
Shan W. Shengcai Shi Sekimoto Y. Noguchi T. 《Microwave and Wireless Components Letters, IEEE》2007,17(4):268-270
We have investigated the effect of a moderately strong magnetic field (up to 1200 Gauss, 13 quantum fluxes within a single junction) on the heterodyne mixing performance of a 385-500GHz superconductor-insulator-superconductor mixer. Both experimental and numerical results indicate that the mixer conversion gain can be significantly reduced by a magnetic field. Surprisingly, the mixer noise shows very weak dependence. The overall receiver noise increase is merely caused by the intermediate frequency noise contribution amplified by a factor of gain reduction. At the expense of little system noise degradation, a relatively strong magnet field can make the mixer more stable at the bias point corresponding to its noise minimum 相似文献
20.
In this paper, we propose a method that builds power model template according to input transi- tions of combinatorial logic circuit. By computing its cor- relation with the overall power consumption of a crypto- graphic circuit, we are able to recover the secret key. Sev- eral simulation-based experiments have been conducted, which verifies the feasibility of our method and shows that the combinatorial logic is also faced with the problem of information leakage in power analysis cases. Compared with DPA (Differential power analysis) and CPA (Corre- lation power analysis), our attack is fairly effective against the cryptographic circuits whose protection is only imple- mented on the register parts of the sequential circuit. In addition, a few topics for further research, as well as the ad- vices for more precise power model and countermeasures, are presented at the end of the paper. 相似文献