High-Efficiency Subharmonic Oscillations from Silicon Diodes at Frequencies up to 6 GHz

Pulsed operation of Si avalanche diodes in an oscillator circuit has produced efficiencies exceeding 45 percent at frequencies of 2.0 to 3.0 GHz, and 17 percent at 6.4 GHz. The device has a lightly punched-through structure working in a coaxial cavity, which can support both the fundamental IMPATT and its subharmonic frequencies.     

Fully integrated W-band microstrip oscillator

A fully integrated microstrip oscillator is described. The active element is an InP transferred-electron device operating in its fundamental mode of oscillation. For measurement purposes, the oscillator structure is mounted in a test assembly and fitted with a waveguide to microstrip transition. Output powers of 16 mW have been observed at the waveguide output port at frequencies in the range 80 GHz to 83 GHz. Transition and circuit losses are approximately 3 dB indicating a device output power of 32 mW.     

A Ring-Oscillator-Based Wide Locking Range Frequency Divider

This letter proposes a wide locking range injection locked frequency divider (ILFD) and describes the operation principle of the ILFD. The circuit is made of a dual band two-stage differential complementery metal–oxide–semiconductor (CMOS) ring oscillator and is based on MOS switches directly coupled to the differential outputs of the ring oscillator. The divide-by-two ILFD can provide wide locking range and the measurement results show that at the supply voltage of 1.8-V, the divider free-running frequencies are 1.36GHz and 2.3GHz, and at the incident power of 0dBm, the locking range is about 1.75GHz from the incident frequency 1.9GHz to 3.65GHz at low band and 2.55GHz from 2.95GHz to 5.5GHz at high band.     

Millimeter-Wave (W-Band) Quartz Image Guide Gunn Oscillator

Dielectric image-guide Gunn oscillator using fused quartz as the guide material has been investigated at frequencies around 94 GHz. Computer-controlled CO/sub 2/ laser cutting of quartz to the designed image-guide patterns has also been achieved. A resonant disk and pin bias circuit was used to tune the oscillator to an output power of 5 mW at the oscillation frequency of 94.2 GHz. An electronic frequency tuning of 350 MHz was measured with the oscillation characteristics similar to waveguide cavity oscillators. By varying the bias circuit disk and pin parameters, the Gunn-oscillator tuning characteristics have also been recorded for the future circuit performance optimization.     

Resonant-tunnelling diode oscillator using a slot-coupled quasioptical open resonator

A resonant-tunnelling diode has oscillated at X-band frequencies in a microwave circuit consisting of a slot antenna coupled to a semiconfocal open resonator. Coupling between the open resonator and the slot oscillator improves the noise-to-carrier ratio by about 36 dB relative to that of the slot oscillator alone in the 100-200 kHz range. A circuit operating near 10 GHz has been designed as a scale model for millimetre- and submillimetre-wave applications.<>     

Two-stage chaotic Colpitts oscillator

A novel version of the chaotic Colpitts oscillator is proposed. It contains two bipolar junction transistors coupled in series. The resonance loop consists of an inductor and three capacitors. The two-stage oscillator, compared with the classical circuit, enables the fundamental frequency of chaotic oscillations to be increased by a factor of three. The PSpice simulations performed with 9 GHz threshold frequency transistors demonstrate that the highest fundamental frequencies of chaotic behaviour are 1 and 3 GHz for the classical and the two-stage Colpitts oscillator, respectively     

Progress with CW IMPATT Diode Circuits at Microwave Frequencies

Progress with CW operation of IMPATT diodes at frequencies up to 20 GHz is reviewed, with emphasis on their circuit applications. Noise properties, stability criteria, and relliability are discussed. Comparisons are made between flat-profile and modified-Read-profile diodes. Examples of oscillator and amplifier circuits are presented.     

A compact full MMIC module for Ku-band phase-lockedoscillators

A compact Ku-band phase-locked oscillator module has been developed in a full MMIC (monolithic microwave integrated circuit) configuration. The module includes an MMIC voltage-controlled oscillator, an analog frequency divider, and interstage amplifiers. The constituent monolithic chips are integrated in a very small single-package module and operate at the target frequencies without any external trimming or matching network. The oscillator is tuned more than 1 GHz with a constant output amplitude. The frequency-divided output is also obtained over the whole tuning range. Spurious output is not found at any frequency up to 22 GHz. In spite of the very low-Q factor of GaAs monolithic circuitry, the oscillator phase noise exhibited is less than -80 dBc/Hz, due to the high-gain, high-speed phase lock     

A Wide Locking Range LC-Tank Injection-Locked Frequency Divider

This letter proposes a wideband injection-locked frequency divider (ILFD) and describes the operation principle of the ILFD. The circuit is made of a differential CMOS LC-tank oscillator and is based on the direct injection topology. The wideband function is obtained by tuning the switch across the tank inductors. The divide-by-two ILFD can provide wide locking range and the measurement results show that at the supply voltage of 1.8 V, the dual-band divider free-running frequencies are from 1.77 to 2.17 GHz for the low-band mode, and from 2.59 to 3.2 GHz for the high-band mode. At the incident power of 0 dBm, the locking range is about 1.7 GHz from the incident frequency 3.31 to 5.01 GHz at low band and 4.06 GHz from 3.94 to 8.0 GHz at high-band mode. The circuit can be used as a single wideband ILFD.     

Microwave Varactor Tuned Transistor Oscillator Design

An analysis is made of the common base microwave transistor oscillator circuit which uses a varactor in series with the colIector to tune over octave bandwidths. Equations are derived giving the required feedback capacitances and resonating elements required for octave tuning. Normally, the collector-emitter capacitance C/sub ce/ is made approximately equal to the transistor collector capacitance C/sub c/. The emitter-base capacitance C/sub eb/ is important only at very high frequencies. It is shown that a high-Q varactor must be used and that only a limited amount of collector-base capacitance C/sub cb/ may be added if the circuit is to be resonated over an octave. The output power for such a circuit is normally about 1/5 the maximum power available from the transistor. Experimental oscillators were made from 0.5 to 1 GHz and 1 to 2 GHz which substantially verified the analysis. Using the TIXS13 transistor, an output power of 200 mW was obtained from 430 to 860 MHz tuning from -2 to -115 volts. In the 1 to 2 GHz range a TIXS13 transistor oscillator was tuned from 1.09-1.96 GHz with about 40 mW power tuning from -2 to -115 volts. By use of a lower case capacitance varactor, the 1 to 2 GHz oscillator could be made to tune over the full octave.     

Planar FET oscillators using periodic microstrip patch antennas

An integrated oscillator/antenna is presented that uses a single microstrip leaky-wave structure as both the resonant and the radiating element. This resonant antenna is connected to a GaAs metal-semiconductor field-effect transistor which acts as the negative resistance element in the oscillator circuit. This type of oscillator is similar in its operating principle to one reported using Gunn diodes and a periodically notched dielectric image guide. This circuit exhibits the high DC-RF conversion efficiency that is typical of field-effect transistor oscillators. The planar circuit is simple and inexpensive to construct, occupies a small volume, and can conform to different surface profiles. Such circuits are suitable for use in millimeter-wave systems as well as at microwave frequencies. A design procedure is given, and the performance of X-band prototype circuits is reported. Prototype circuits showed a 9 dB isotropic conversion gain and 40 MHz tuning range at 9.5 GHz     

基于ADF4113的本振扫频源的设计与实现

运用数字锁相频率合成的思想,以AD I公司生产的数字分频器和鉴相器ADF4113为核心,设计了频率范围在1.58 GHz~1.78 GHz的本振扫频源。重点阐述了系统的硬件实现,包括系统设计方案、主要电路单元设计以及系统测试结果等,并对该系统在实际调试过程中常见的问题进行了详细的分析。     

Large-Signal Equivalent-Circuit Model of a GaAs Dual-Gate MESFET Mixer (Short Papers)

A large-signal equivalent-circuit model of a GaAs MESFET mixer containing twelve elements, of which eight are voltage-dependent, is solved in the time domain for Iocal oscillator and frequencies of 9.5 GHz and 10.0 GHz, respectively. The results variation of conversion gain with local oscillator and signal power and are in good agreement with measured values. The model is formulated in such a way that material/device/circuit interactions can be yielding information on the preferred device structures and biasing conditions.     

Microwave characterization of a resistive-gate MESFET oscillator

Measurements of microwave oscillations in resistive-gate MESFET contiguous-domain oscillator devices are discussed. Oscillation frequencies in the ranges from 22 to 30 GHz and 37 to 42 GHz are observed independently of the device length, and frequency can be tuned during operation by varying the source-to-gate voltage. Evidence suggests that the observed signals are harmonics of a fundamental signal in the range from 11 to 15 GHz. While the possibility that conventional transit-time Gunn domain propagation is occurring in this frequency range cannot be ruled out, the fact that frequency is independent of channel length suggests that contiguous domains are forming, at least in the longer devices. Because of its structure, the resistive-gate MESFET oscillator can be easily incorporated into MESFET integrated circuits for MMIC (monolithic microwave integrated circuit) applications     

A subharmonic self-oscillating mixer with integrated antenna for60-GHz wireless applications

A balanced integrated-antenna self-oscillating mixer at 60 GHz is presented in this paper. The modal radiation characteristics of a dual-feed planar quasi-Yagi antenna are used to achieve RF-local oscillator (RF-LO) isolation between closely spaced frequencies. The balanced mixer is symmetric, inherently broad band, and does not need an RF balun. Pseudomorphic high electron-mobility transistors are used in a 30-GHz push-pull circuit to generate the second harmonic and a 30-GHz dielectric resonator was used to stabilize the fundamental oscillation frequency. This allows the possibility of building a balanced low-cost self-contained antenna integrated receiver with low LO leakage for short-range narrow-band communication. Phase locking can be done with half of the RF frequency. The circuit exhibits a conversion loss less than 15 dB from 60 to 61.5 GHz, radiation leakage of -26 dBm at 60 GHz, and IF phase noise of -95 dBc/Hz at 100-kHz offset     

Local Oscillator Generation Circuit for Direct Conversion Transmitter

In this paper a fully monolithic on-chip local oscillator signal generation circuit is presented for eliminating the negative effect of coupling between bond-wires, package pins and output and input lines of the power amplifier output to the local oscillator input for direct conversion transmitters. The proposed circuit generates the local oscillator signal at frequencies 1710–1785 GHz which is harmonically uncorrelated from two input signals at 464 MHz and 1792–2088 MHz. The required building blocks are a frequency divider, a mixer and an active band-pass filter. Fully monolithic high frequency band-pass filters have not been available until recently, and the designed circuit is in fact one of the first applications reported for MMIC active filters in cellular phones. The circuit is designed with a 0.5 m GaAs MESFET technology and the performance is verified with on-chip measurements.     

High-performance millimetre-wave suspended stripline Gunn VCO

A novel millimetre-wave integrated circuit Gunn voltagecontrolled oscillator (VCO) has been developed with high output power using suspended stripline. An output power of 100 to 150mW has been achieved at frequencies between 33 and 42 GHz. A varactor diode was mounted in alignment and in close proximity to the Gunn diode to achieve an electronic tuning range of 300 MHz     

A 2.4-GHz silicon bipolar oscillator with integrated resonator

A 2.4 GHz fully-monolithic silicon-bipolar oscillator circuit implemented in a 12 GHz BiCMOS technology is presented. The integrated resonator circuit uses three different versions of a 2 nH multilevel inductor and a wideband capacitive transformer. The measured Q factor is 9.3 for the three-level inductor. An oscillator phase noise of -78 dBc/Hz is achieved at 20 kHz offset. The circuit dissipates 50 mW from a 3.6 V supply     

Simulation Study of Harmonic Oscillators

In the last few years, the operating modes of Gunn oscillators for frequencies above 60 GHz have been discussed controversially. In this context, a general theoretical circuit model for oscillators operating in the fundamental and in the second-harmonic modes is studied. The model employs a simple cubic I - V characteristic of the active element and separate embedding circuits for the fundamental and second-harmonic frequencies. The current and voltage waveforms of both modes are contrasted. The oscillator source impedances and the external Q of the second-harmonic mode oscillator are calculated.     

Self-calibrated quadrature generator for WLAN multistandard frequency synthesizer

A self-calibrated quadrature generator capable of generating local oscillator (LO) outputs for IEEE 802.11a-b is presented. The quadrature generator is embedded in a frequency synthesizer that generates reference frequencies at 2.4 and 5GHz. A new sequential calibration scheme maintains the quadrature at the 5-GHz output within a maximum phase error of 2/spl deg/, while a divide-by-two flip-flop generates the quadrature output at 2.4 GHz. The circuit is fabricated in a 0.25-/spl mu/m SiGe BiCMOS technology and occupies a silicon area of 2 mm/sup 2/; the quadrature generator consumes a current of 5 mA from a 2.5-V supply.