三毫米波亚谐波混频器研制

采用鳍线结构研制出三毫米波亚谐波混频器.混频的核心元件是反向并联的GaAs梁式引线肖特基势垒二极管对.根据亚谐波混频器对本振、射频和中频网络的要求,先用谐波平衡法分析出反向并联二极管对在本振信号单独激励下的大信号阻抗,由此设计出本振网络.然后模拟出该器件在大信号本振激励下的小信号射频输入阻抗,并由此设计出射频网络.中频网络采用微带线结构实现.该混频器工作在射频92～96GHz,中频8～12GHz,实测带内变频损耗小于19.1dB.     

毫米波谐波混频器

本文详细地论述了谐波混频器的工作原理,导出了变频参数表达式、这些公式虽近似,但却为设计和调试提供了理论依据.用单个二极管构成的八毫米谐波混频器,当谐波次数为12时,得到的变频损耗小于40dB 信号至本振端口的隔离大于20dB.     

Y波段固态谐波混频器研究

为了进一步降低太赫兹接收机的噪声,介绍了基于平面肖特基二极管实现低噪声太赫兹谐波混频器的方法。在建立肖特基二极管较为精确的三维模型和电气模型的前提下,引入紧凑型hammer-head 滤波器结构,同时结合低损耗石英固态电路混合集成的方法,研制了220GHz 和250GHz 太赫兹谐波混频器。测试表明:220GHz混频器在205～235GHz工作范围内最低双边带变频损耗小于6.5dB,最低噪声温度小于650K,250GHz 混频器在230～270GHz 工作范围内最低双边带变频损耗小于6.5 dB,最低噪声温度小于900K。     

超宽带谐波混频器的设计

叙述了一种超宽带谐波混频器的原理、设计以及测试结果。该混频器主要由微带线巴伦、倍频器、单平衡混频器三部分组成。按中心频率为4.5 GHz设计出微带线巴伦结构,平衡端口输出相位差180°,具有尺寸小、损耗低、幅度相位一致性好等优点;采用AEROFLEX公司的MSPD2018型相位检波器作为混频器,该混频器采用阶跃恢复二极管倍频器与单平衡混频器并联结构,先倍频n次谐波后再与信号进行混频;传输线为四分之一波长线以提高端口间隔离度;利用微波电路仿真软件ADS对混频器进行基波和谐波分析。测试结果表明,在3～25 GHz的频率范围内,本振至中频的隔离度优于66 dB,其变频损耗的实测结果满足设计要求,在现有的宽带混频器中具有较好性能。     

毫米波谐波混频器扩频技术

文章主要介绍了3mm谐波混频器的设计方法并用于毫米波扩频,对毫米波宽带匹配技术、宽带滤波桥路技术、毫米波电路加工及微组装工艺也作了阐述。毫米波谐波混频器采用波导和带状线混合结构,混频二极管采用梁式引线二极管对,滤波电路采用带状线结构的高低通滤波器。毫米波信号与本振信号的18次谐波混频,输出一个中频信号,通过与安捷仑的8563EC、8566等频谱议的配合使用,达到频谱仪的扩频,也可用于网络分析仪、频率综合器、频率计等仪器的扩频。     

0.12THz谐波混频器的设计与研究

在太赫兹通信、雷达、电子对抗、测量等系统中,所遇到的首要问题便是太赫兹波信号的频率变换,谐波混频器是太赫兹通信系统中最为核心的器件,其性能的好坏将直接决定接收系统和发射系统的性能,本文对0.12THz的二次谐波混频器进行理论分析,在理论分析的基础上对该混频器进行设计仿真,理论仿真结果表明0.12THz的二次谐波混频器的损耗小于8dB,并对于优化后的模型在RT/duroid 5880为电路基片上进行加工测试,测试结果表明本文设计的0.12THz二次谐波混频器衰减为7dB,已经达到了国际先进水平。     

Ku频段谐波混频器的研制

叙述了一种可用于Ku频段微波接收机的谐波混频器的原理、设计、仿真及实验结果.该混频器主要由Lange耦合器、输入、输出滤波器以及匹配网络等部分组成.实验结果表明,在14.00～14.25GHz的频率范围内变频损耗的实测曲线与仿真曲线基本吻合,带内幅度平坦度优于1dB,驻波比小于2.     

14／12GHZ谐波混频器

本文叙述了一种可用于微波接收机的１４／１２ＧＨＺ谐波混频器的原理、设计、仿真及结果。该混频器主要由Ｌａｎｇｅ耦合器、输入、输出滤波器以及匹配网络等居１４．００－１４．２５ＧＨＺ的频率范围内变频增益为－１６．５２ｄＢ,带内平坦度优于１ｄＢ,驻波比小于２。     

用谐波平衡法分析DGFET混频器

本文采用谐波平衡法分析了ＤＧＦＥＴ混频电路，给出了设计计算公式，利用此结论研制的实际电路取得了令人满意的结果。     

A Study of W-Band Subharmonically Pumped Mixer

A W-band subharmonically pumped mixer with packaged Schottky diodes has been developed. The design and performance of this mixer are described in detail. A new method for measuring the embedding network parameters of the subharmonically pumped mixer has been developed and the measurement bas been carried out directly at 2f/sub LO/ and 2f/sub LO/+-f/sub if/. A special program for the analysis of the subharmonically pumped mixer has been developed, and computed results are given in comparison with measured results.     

Wide-Band Subharmonically Pumped W-Band Mixer in Single-Ridge Fin-Line

A subharmonic mixer is described that has an instantaneous bandwidth of 11 to 14 GHz centered near 95 GHz. A wide bandwidth is achieved by the close integration of a low-capacitance diode mount, printed circuit matching elements, and simple yet effective filters which are uniquely suited to realization in a single-ridge fin-line. The mixer also has a two-terminal shunt mount that will accept two conventional beam-lead diodes or a single dual-junction device. With the latter, a minimum conversion loss of 8.5 dB has been achieved with a drive level of only 4 dBm at 45 GHz.     

A Planar Quasi-Optical Subharmonically Pumped Mixer Characterized by Isotropic Conversion Loss

By using a subharmonically pumped circuit in a quasi-optical planar mixer, we have found it possible to use an LO frequency of one-half the normaf value with little added circuit complexity. This circuit shows conversion loss as low as 8.6dB +- 2 dB at 14 GHz. Through the means of a newly defined quasi-optical mixer parameter called isotiopic conversion loss (L/sub iso/), we find that performance of the mixer system degrades less than 10 dB from an RF input of 14 GHz to 35 GHz, which is more than twice the designed RF frequency.     

Subharmonically Pumped Millimeter-Wave Mixers

The two-diode subharmonically pumped stripline mixer has a pair of diodes shunt mounted with opposite polarities in a stripline circuit between the signal and local oscillator inputs. The circuit has low noise and conversion loss and substantial AM local oscillator noise cancellation.The local oscillator frequency is about half the signal frequency. A novel diode chip, the notch-front diode, which has ohmic contacts on the chip faces adjacent the face containing the diode junctions, was developed for these circuits. The notch-front diode permits the low parasitic reactance of the waveguide diode mount to be achieved in stripline circuits. The best performance for a two-diode subharmonically pumped mixer with notch-front diodes was a 400 K mixer noise temperature, obtained at 98 GHz which is comparable to the best fundamental mixers in this frequency range. The performance over a 47-110-GHz frequency range for this circuit with commercial beam-lead diodes is also presented.     

Subharmonically Pumped RF CMOS Paramps

This paper discusses MOS-based RF integrated parametric amplifiers and converters (paramps). Specifically, MOS varactor characteristics are exploited to support subharmonically pumped configurations. Such configurations require lower frequency pumping, and thus, are more accommodating to CMOS pumps for millimeter-wave applications. Closed-form expressions are derived for the optimally biased accumulation-mode MOS varactor elastance based on pumping voltage, channel doping, and gate oxide thickness. Simple design equations for the pumped figure of merit, a metric common to all small-signal paramps, are obtained, resulting in a compact means of predicting integrated circuit performance. A comparison is made between MOS-based and diode-based designs (traditional and subharmonic) for a downconverting paramp topology. The importance of deep-depletion behavior is discussed.     

Superconducting Tunnel Junctions As Mixers at 115 Ghz

Superconducting tunnel junctions have been used as the nonlinear element for mixing at a signal frequency of 115 GHz. The experimental results are compared with predictions of a theoretical analysis based on the quantum theory of mixing of J. R. Tucker. Qualitative agreement is obtained and suggestions are made for quantitative reconciliation. The junctions were small area (/spl equiv/0.4mu m/sup 2/) with normal resistances of 60 to 100 omega and capacitance approximately 20 fF. Measured sensitivity (T/ sup SSB/sub MXR/=62 K, L/sub c/=7.6 dB) implies receiver noise temperatures superior to the best receivers now in use at this frequency.     

A 320–360 GHz Subharmonically Pumped Image Rejection Mixer Using Planar Schottky Diodes

This letter presents the design, fabrication and test of an integrated 320–360 GHz subharmonic image rejection mixer using planar Schottky diodes. The integrated circuit uses two separate anti-parallel pairs of diodes mounted onto a single quartz-based circuit. Measurement results give best single sideband (SSB) receiver noise temperatures of approximately 3400 K at 340 GHz, with an image rejection from 7.2 to 24.1 dB over the 320–360 GHz frequency band. This work represents the first demonstration of a Schottky based SSB mixer at submillimeter wavelengths.      

Subharmonically Pumped Schottky Diode Single Sideband Modulator

A subharmonically pumped single sideband Schottky diode modulator is described. Its advantages are a large carrier suppression and Iowered pumping frequency. The experimental 2-GHz MIC modulator pumped with an 8-mW signal exhibits a conversion loss of 6.2-7.3 dB over a 15-percent frequeney band. For a 120-mu W input modulating signal, the unwanted components in the output spectrum are at least 18 dB and mostly over 20 dB below the desired sideband.     

Subharmonically Pumped Millimeter-Wave Upconverters Based on Heterostructure Barrier Varactors

A heterostructure barrier varactor subharmonic upconverter is investigated for the first time. Odd sidebands are suppressed due to the symmetric capacitance–voltage (C–V) characteristic of the varactor and high output power is possible through epitaxial stacking of barriers. The upconverter is pumped using a millimeter-wave local oscillator, and can be used as a transmission-type double-sideband suppressed carrier modulator. The initial measured conversion loss is 8–16 dB at 100 and 200 GHz. The results are significantly improved by using external impedance tuners, which is verified through both simulations and measurements.     

Analysis and Design of a Novel $times$4 Subharmonically Pumped Resistive HEMT Mixer

In this paper, a novel topology of an HEMT-based subharmonically pumped resistive mixer (SHPRM) is presented, i.e., the times4SHPRM. The presented topology requires only a quarter of the local oscillator (LO) frequency compared to a fundamentally pumped mixer (e.g., 15 instead of 60 GHz in a 60-GHz system). This reduction in required LO frequency provides a significant reduction in complexity of the overall radio front-end and reduces the dc power consumption as well as the occupied chip area. Thus, the times4SHPRM provides a significant cost reduction for a millimeter-wave system. Furthermore, the times4SHPRM can be used for both up- and down-conversion and it can be implemented in any field-effect transistor technology. The principle of the times4SHPRM is presented and wave analysis is applied in order to investigate the fundamental limitations of this mixer topology. For an evaluation of the times4SHPRM topology, three different monolithic microwave integrated circuits (MMICs) were designed and manufactured in the same MMIC metamorphic HEMT technology. Besides measured performance of the times4SHPRM, a traditional times2SHPRM and a single-ended resistive mixer were implemented and their performances are presented and compared. All of these MMICs operate with a 60-GHz RF frequency and employ LO signals close to 15, 30, and 60 GHz, respectively.