Determination of HEMT's noise parameters versus temperature usingtwo measurement methods

A simplified approach for the determination of the noise parameters of high electron-mobility transistors (HEMT's) at microwave frequencies has already been presented for devices tested at room temperature. Such method relies on the extraction of a noisy circuit model from measurements of the scattering parameters and the noise figure at the fixed source impedance of 50 Ω (namely, F₅₀ ). The noise parameters of the device are then computed by model simulation. They exhibited a very good agreement with the noise parameters determined by the experimental procedure. In the present work, commercial pseudomorphic HEMT'S have been characterized at different temperatures in the 6 GHz to 18 GHz frequency range for validating the use of a further simplified procedure. We here show how to determine the complete noise performance of the devices from a very reduced set of measurements, i.e., the scattering parameters at each selected temperature and the F₅₀ noise figure at room temperature. The computed noise parameters are compared with those determined by application of the measurement procedure. The results show that the very simplified method can be employed with a good degree of accuracy whenever rapid noise testing of HEMT's versus temperature is needed     

A Millimeter Wave Complex Reflection Coeficient Scanner

A broadband microwave measurement system has been designed to make complex reflection coefficient measurements on a swept basis at millineter wave frequencies. This instrument covers a frequency range of 50-75 GHz in WR-15 rectangular waveguide. Two appliques are being added in WR-22 and WR-10 waveguide to extend the frequency range of the system to 33-110 GHz. Measurements can be made while sweeping over bands as wide as 10 GHz. An interesting feature of the complex reflection coefficient scanner is that residuals, or baseline, of the system are automatically subtracted. The resultant output display is a real-time polar plot of the actual reflection coefficient of the network under test. Residuals of 0.03 for reflection coefficients around unity, and 0.013 for reflection coefficients around zero can be measured with a resolution of 0.01 while sweeping over a 5 GHz band. A maximum reflection coefficient range of 46 dB has been achieved using straightforward video detection techniques. For measurements of networks with very low reflection coefficients (0.01 and lower) a time averaging feature is available to reduce the effects of random noise. The complex reflection coefficient of the unknown can be displayed on an oscilioscope and photographed, or read out on an X-Y plotter.     

Microwave bulk-acoustic-wave reflection-grating resonators

A technique for fabrication of bulk-acoustic-wave (BAW) resonators operating at fundamental frequencies between 1 and 10 GHz is presented. The resonators utilize a reflection grating made by optical holographic methods in iron-doped lithium niobate. Q factors of 30000 at 1 GHz have been demonstrated. Extension to Q of 10000 at 10 GHz appears feasible. Projected limitations to performance are discussed. The high Q at the high fundamental frequency directly results in low-phase noise. Phase-noise measurements of BAW resonator-stabilized oscillators operating at 1.14 GHz are presented. The single-sideband noise floor of <-140 dBc/Hz is shown to be in agreement with an analytical model. Projected improvements in the devices and circuits promise performance of <-160 dBc/Hz.     

High Q-factor microwave Fabry-Perot resonator with distributed Bragg reflectors

A Fabry-Perot resonator operating at 39 GHz, with two pairs of quarter-wavelength single-crystal quartz Bragg reflectors has been realized. For the length of 98.26 mm, its Q-factor is about 560,000, which is 4.3 times better than for the same resonator without Bragg reflectors. Rigorous finite-difference frequency-domain analysis has been applied to the problem and is compared with simplified semi-analytical solutions. Good agreement between theoretical and experimental resonant frequency and Q-factors has been obtained. Thermal compensation of the resonant frequency of the Fabry-Perot has been proposed employing rods and cylinders made of metals with different thermal expansion coefficients.     

Low power design of CMOS 5-GHz voltage-controlled oscillator from narrowband to wideband with switching capacitor module

In this study, we demonstrated low power and low phase noise of the complementary cross-coupled voltage-controlled oscillators (VCOs). Two chips are implemented by TSMC standard 0.18-mum complementary metal-oxide semiconductor (CMOS) process. The first one that employed a memory reduction tail transistor technique is operated from 5.17 to 5.85 GHz at a supply voltage of 1.2 V whereas its tuning range is 12.3%. The power consumption is 1.8 mW whereas the measured phase noise is -126.6 dBc/Hz at 1-MHz frequency offset from 5.17 GHz. The other employed switching capacitor modules to achieve wide tuning range and minimise phase noise, it operated from 3.64 to 5.37 GHz with 38% tuning range. The power consumption is 13.7 mW by a 1.8 V supply voltage and the measured phase noise in all tuning ranges is less than -122 dBc/Hz at 1-MHz frequency offset.     

Noise parameter measurement of microwave transistors at cryogenictemperature

A major drawback of active two-port microwave noise parameter measurement, by means of the multiple impedance technique at cryogenic temperature, lies in that a nonnegligible part of a lossy transmission line featuring a nonuniform temperature must be inserted between the automatic tuner (operated at room temperature) and the device input. Since the temperature distribution over that line is not precisely known, the contributed noise cannot be directly corrected. To overcome this, the use of a noise de-embedding technique is proposed, based on the measurement of a suitable noise standard made of a cooled mismatched two-port. By way of example, noise parameters of a GaAlAs/GaAs HEMT measured between 14 and 18 GHz at 77 K are reported. Finally, the accuracy of this technique is discussed     

A free-space bistatic calibration technique for the measurement ofparallel and perpendicular reflection coefficients of planarsamples

A free-space bistatic measurement system suitable for operation in the frequency range of 5.85-40 GHz is calibrated to measure the parallel and perpendicular reflection coefficients of metal-backed planar samples for obliquely incident waves. The measurement system consists of transmit and receive antennas in the bistatic configuration, mode transitions, precision coaxial cables, and the network analyzer. Diffraction effects of the edges of the sample are minimized by using spot-focusing horn lens antennas, which focus most of the energy on a one-wavelength-diameter circular section of the sample. A new free-space bistatic calibration technique is developed to eliminate errors due to multiple reflections between transmit and receive antennas via the surface of the sample. The effect of defocusing due to the obliquely incident plane wave with focused antennas is minimized by introducing correction factors which modify measured reflection coefficients. Details of the calibration procedure and a discussion of the experimental results obtained for planar samples of Teflon and Eccogel 1365-90 in the frequency range 12.4-18 GHz are presented     

Measuring Frequency Response of a Single-Walled Carbon Nanotube Common-Source Amplifier

Frequency response function (FRF) showing ac gain from a single-walled carbon nanotube transistor is presented. A top-gated carbon nanotube FET (CNFET) is configured as a common-source amplifier and the FRF of the amplifier is measured. Evidence of unambiguous signal amplification is observed in time domain as well as frequency domain up to a unity voltage gain frequency of approximately 560 kHz. The observed roll-off in frequency is solely due to the RC time constant of the measurement apparatus. A specifically designed circuit-compatible SPICE model for the CNFET is used to model both dc and ac characteristic with the same set of physical parameters. Good agreement between measurement and simulation is obtained. For a device without the parasitic load capacitance, we predict an intrinsic unity voltage gain frequency of 29 GHz and a cutoff frequency of $sim {50}$ GHz.      

Complex permittivity measurements of ferroelectrics employing composite dielectric resonator technique

Composite cylindrical TE(0n1) mode dielectric resonator has been used for the complex permittivity measurements of ferroelectrics at frequency about 8.8 GHz. Rigorous equations have been derived that allowed us to find a relationship between measured resonance frequency and Q-factor and the complex permittivity. It has been shown that the choice of appropriate diameter of a sample together with rigorous complex angular frequency analysis allows precise measurements of various ferroelectric. Proposed technique can be used for materials having both real and imaginary part of permittivity as large as a few thousand. Variable temperature measurements were performed on a PbMg(1/3)Nb(2/3)O3 (PMN) ceramic sample, and the measured complex permittivity have shown good agreement with the results of measurements obtained on the same sample at lower frequencies (0.1-1.8 GHz).     

A Heterodyne Low-Level Signal Phase Meter Operating over 1 MHz to 300 MHz

After giving a brief summary of the main devices allowing the measurement of phase shifts between two sine signals in the approximate range 1 Hz-1 GHz, we propose a new apparatus for measuring phase shift. The principle of this apparatus uses a heterodyne technique in association with a phase-locked loop which brings about frequency translation of the measured signals. The intermediate frequency which is obtained is small with respect to the frequencies studied conveying a high degree of selectivity to the apparatus. This allows measurements to be made on signal with noise or low-level signal while also maintaining good accuracy. For a system operating from 1-300 MHz, we have obtained phase linearity of ± 1°, resolution of 0.1°. In obtaining the accuracy of ± 5°, the sensitivity is -86 dBm in the 1-30-MHz frequency range; with 300 MHz the sensitivity reached is -68 dBm.     

Nondestructive determination of electromagnetic parameters ofdielectric materials at X-band frequencies using a waveguide probesystem

An accurate technique used to measure complex permittivity and permeability of isotropic materials simultaneously has been developed by employing a flanged open-ended rectangular waveguide probe over a frequency range of 8-12 GHz. Two coupled integral equations for the aperture electric field are formulated and solved numerically using Galerkin's method. A series of experiments has been conducted, and the calibration of the probe system using an adjustable shorter is explained. The inverse results on the electromagnetic (EM) properties of various materials (including solid and liquid materials) based on the measured reflection coefficients of the incident dominant mode are presented. It is also shown that the EM parameters of isotropic materials having low complex permittivities can be determined accurately, while those with higher complex permittivities cause larger measurement errors     

Circuit co-simulation and measurement techniques applied to voltage-controlled oscillator design

A voltage-controlled oscillator (VCO) was designed for operation in C-band for use in a microwave pointto- point radio system. Microstrip technology was chosen for resonator implementation since it offers ease of manufacturing and frequency adjustment. The design was performed using an electromagnetic harmonic balance co-design technique in conjunction with linear analysis in order to achieve first pass success. Emphasis in this work is the ability to use multiple design approaches and test techniques while validating in advance with co-simulation. The measured frequency against tune voltage data shows excellent agreement with simulation. Maximum deviation of 2% between the two was observed. The VCO tuned from 4.3 to 5.4 GHz as the tuning voltage was varied from 0 to 9 V representing a tuning bandwidth in excess of 20%. Power dissipation is 150 mW. Phase noise over the tune range was better than 2108 dBc/Hz at 100 kHz offset. The oscillator design efficiency, applicable to wider tune range designs, is greater than 2%. The hybrid oscillator figure-of-merit functions evaluated in this work exceeded comparable silicon-integrated implementations.     

Calculation of the Noise Temperature of Microwave Transistor Low-Temperature Noise Generators

A method of calculating the noise temperature of a microwave transistor low-temperature noise generator by using reference data on the noise parameters and the coefficients of the scattering matrix of the transistor is developed for the 8–40 GHz frequency band.     

An optical self-calibrating technique for the dynamiccharacterization of PZT's

A system suitable for the measurement of linear sinusoidal vibration amplitudes is described. The signal beam of a Michelson interferometer is focused on the vibrating target while a suitable phase noise is applied to the reference arm of the interferometer. Signal processing is based on the null adjustment of the Bessel coefficients J₁ and J₂ derived from the signal provided by a single photodiode placed in the center fringe of the interference pattern. The system has been shown to be self-calibrating and intrinsically immune to mechanical perturbations induced in the interferometer. The technique proposed has been experimentally demonstrated by measuring the vibration amplitude of a PZT device in the amplitude range from 0.4 to 1.7 μm and in the frequency range from 8 to 22 kHz     

Dielectric characteristics of ore minerals in a 10–40 GHz frequency range

A new approach to investigation of the complex dielectric permittivity of both nonmetallic and ore minerals in the microwave frequency range is proposed. Using this approach, data on the complex permittivity of sphalerite, magnetite, and labradorite in a 10–40 GHz frequency range have been obtained for the first time. A method is proposed for calculating the complex permittivity from experimentally measured frequency dependences of the reflection and transmission coefficients of a plane-parallel plate of a given mineral. Approximate expressions that can be used for calculations of the complex refractive index and permittivity of minerals are presented.     

Radio-frequency front-end for 5 GHz wireless local area network transceivers

A transceiver front-end for 5 GHz wireless local area network applications has been designed and implemented in a low-cost 46 GHz f_r pure-silicon bipolar technology. The transceiver front-end adopts a superheterodyne sliding-IF architecture and consists of a down-converter, an up-converter and an LO frequency synthesiser. By exploiting a 1 bit variable-gain low-noise amplifier, the down-converter is able to provide an excellent noise figure of 4 dB while ensuring an input 1 dB compression point of 210 dBm with a current consumption of 25 mA from a 3 V supply voltage. The transmitter front-end is implemented by means of a current-reuse variable-gain up-converter. The circuit provides an output 1 dB compression point of 5.3 dBm although consuming only 45 mA from a 3 V supply voltage. Moreover, a linear-in-dB gain control characteristic is achieved over a 35 dB dynamic range. The LO frequency synthesiser is implemented by means of an integer-N phase-locked loop. It features a phase noise of 2117 dBc/Hz at 1 MHz offset from the centre frequency of 4.1 GHz and exhibits a tuning range of 1.2 GHz, from 3.47 to 4.65 GHz. The LO frequency synthesiser draws 20 mA from a 3 V supply voltage.     

Temperature dependent study on the microwave noise performance of metamorphic InP/InGaAs heterojunction bipolar transistors

In this study, a detailed characterization on the microwave noise performance of high gain metamorphic heterojunction bipolar transistor (MHBT) in the temperature range of 300 K to 380 K is performed. The results are compared between the MHBT and the referenced lattice-matched InP HBT (LHBT) devices. The minimum noise figure (NF_min) versus frequency in the range of 2 to 20 GHz at different temperatures for a 1.6 × 20 μm² HBTs are measured. The experimental results show that the MHBT exhibits a slightly larger variation in NF_min compared to lattice-matched HBTs. Even though the MHBTs may have much higher thermal resistance, this may not significantly affect the device microwave noise performance.     

Experimental characterization of on-chip inductor and capacitor interconnect: part II. Shunt case

We present a wide-band experimental characterization of an on-chip shunt inductor and capacitor (LC) interconnect. (A previous paper by the authors considered the series LC case). In order to capture the effects of parasitic parameters on the wide-band transmission and reflection characteristics of shunt LC interconnects, we propose a generalized frequency-independent circuit model for fast-running simulations. The model is accurate to above its second resonant frequency, with low average simulation errors for both reflection and transmission coefficients compared to the measured two-port S parameters over the frequency range of 1 to 14 GHz.     

Phase noise performance of microwave analog frequency dividers: application to the characterization of oscillators up to the millimeter-wave range

The phase noise performance of two different microwave analog frequency dividers is characterized and compared with the values obtained using simple theories of noise in injection-locked systems. The direct measurement of the divider noise with a low phase noise synthesizer is not accurate enough, and the residual noise technique is used. The noise levels observed using this technique, between -120 and -155 dBc/Hz at a 10 kHz offset frequency, demonstrate that this divider noise is much lower than the phase noise of most microwave free running oscillators, even if this noise is still high with respect to the residual noise of amplifiers realized with the same active devices. The down conversion of microwave sources up to 40 GHz, is proposed as an application example.     

Quantum interference filters based on oxide superconductor junctions for microwave applications

We have studied superconducting quantum interference filters (SQIFs) based on bicrystal neodymium gallate substrates, which can be used in the microwave frequency range. The characteristics of a serial SQIF have been compared for the first time with those of a single superconducting quantum interference device (SQUID) and a chain of serially connected SQUIDs with equal areas of superconducting loops. The regime of SQIF operation with a voltage-flux (V-Φ) characteristic determined by the magnetic-field dependence of the critical current in the Josephson junction has been analyzed. It is shown that the output noise of a SQIF measured with a cooled amplifier in the 1–2 GHz range is determined by the slope of the V-Φ characteristic. The influence of a spread in the parameters of Josephson junctions in the SQIF on the integral V-Φ characteristic of the whole structure is considered.