IF Amplifier Research Articles

A Very Low-Noise Integrated 3MM-Wave Schottky Diode Mixer and PHEMT IF Amplifier

An integrated 3mm-wave Schottky diode mixer and pseudomorphic high-electron-mobility transistor (PHEMT) IF amplifier with record noise performance at room temperature is described. The design has shown the room-temperature double-sideband (DSB) receiver noise temperature TRDSB of 190 K at 100 GHz due to a very low conversion loss in the full-height waveguide mixer and an ultra-low noise of the PHEMT IF amplifier. The receiver noise temperature has been reduced by a factor of 1.5 in comparison with the best previously reported 3mm-wave Schottky diode mixer receiver.

High Doping Density Schottky Diodes in the 3MM Wavelength Cryogenic Heterodyne Receiver

The paper describes a 3mm cryogenic mixer receiver using high doping density (“room-temperature”) Schottky diodes. The measured equivalent noise temperature Teq of the diodes is 109 K at 20 K, which is much higher than the Teq of the low doping density (“cryogenic”) diodes. In spite of this, the double-sideband (DSB) noise temperature of the cryogenic receiver developed is 55 K at 110 GHz, owing to the low conversion loss of the mixer and ultra-low noise of the PHEMT IF amplifier. This is the lowest noise temperature ever reported for a Schottky diode mixer receiver. The results obtained are useful for the development of submm receivers in which high doping density Schottky diodes are used.

W-band resistive mixer using metamorphic HEMT

We fabricate single-ended resistive W-band millimeter-wave monolithic IC (MIMIC) mixers based on 0.1 μm InGaAs/InAlAs/GaAs metamorphic HEMT technology. The mixers show good characteristics in linearity and LO-RF isolation, and the mixers with IF amplifiers exhibit a conversion loss of ∼0.4 dB, which is an improvement of ∼7.8 dB compared to that of the mixers without IF amplifiers. We obtain P-1 dB of 10 and 9 dBm from the mixers with and without the IF amplifiers, respectively.

A terahertz focal plane array using HEB superconducting mixers and MMIC IF amplifiers

We present a focal plane array (FPA) designed for operation at terahertz frequencies. The FPA is based on NbN phonon-cooled hot electron bolometer mixers directly coupled to wide-band microwave monolithic integrated circuit IF amplifiers. The array incorporates all the required dc-bias and IF circuitry in a compact split-block design. We present new experimental results describing the optical coupling efficiency to the array, as well as receiver noise temperature measurements. The measurements were performed at 1.6 THz, showing good agreement with theoretical predictions. This is the first low-noise heterodyne focal plane array to be reported for any frequency above 1 THz.

Gain stabilization of a submillimeter SIS heterodyne receiver

We have designed a system to stabilize the gain of a submillimeter heterodyne receiver against thermal fluctuations of the mixing element. In the most sensitive heterodyne receivers, the mixer is usually cooled to 4 K using a closed-cycle cryocooler, which can introduce /spl sim/1%; fluctuations in the physical temperature of the receiver components. We compensate for the resulting mixer conversion gain fluctuations by monitoring the physical temperature of the mixer and adjusting the gain of the IF amplifier that immediately follows the mixer. This IF power stabilization scheme, developed for use at the Submillimeter Array, a submillimeter interferometer telescope located on Mauna Kea, HI, routinely achieves a receiver gain stability of one part in 6000 (rms to mean). This is an order of magnitude improvement over the typical uncorrected stability of one part in a few hundred. Our gain stabilization scheme is a useful addition to superconductor-insulator-superconductor heterodyne receivers that are cooled using closed-cycle cryocoolers in which the 4-K temperature fluctuations tend to be the leading cause of IF power fluctuations.

Development of 60-GHz front-end circuits for a high-data-rate communication system

Recent results from a Swedish program for development of 60-GHz monolithic microwave integrated circuits (MMICs) for high-data-rate communication links are presented. Front-end circuits such as mixers, amplifiers, frequency multipliers, IF amplifiers with gain control, and voltage-controlled oscillators (VCOs) have been realized utilizing GaAs PHEMT and MHEMT technologies. A newly developed 7.5-GHz coupled Colpitt VCO shows a minimum phase noise of -95 dBc at 100 kHz offset. A second-harmonic 14-GHz VCO shows a minimum phase noise of less than -90 dBc at 100 kHz. A novel balanced 7-28-GHz MMIC frequency quadrupler is described and compared with a single-ended quadrupler at the same input frequencies. To demonstrate its feasibility and potential application, the quadrupler is combined with the Colpitt VCO and the output characteristics of the resulting 30-GHz MMIC source are measured. A three-stage MHEMT wide-band amplifier covering 43-64 GHz with a gain of 24 dB, a minimum noise figure of 2.5 dB, and a passband ripple of 2 dB is also described. In future 60-GHz systems for mass markets where cost is of utmost importance, Si-based technologies, especially CMOS, are highly interesting. Some recent circuit results based on a 90-nm CMOS technology are also reported.

Odin, 100– [formula omitted] radiometer design and in-orbit results

The Odin satellite was successfully launched on February 20, 2001 into a low Earth polar orbit to begin its mission to study line emission from both the Earth atmospheric limb and diverse objects such as comets, molecular clouds and galaxies. It is unique that two different scientific disciplines use not only the same spacecraft but also the same instrumentation. Special care had to be taken in the design, to be able to accomplish this. Time is shared on a per day basis with regular stratospheric observations occurring every 3 days. The receiver system is fed by an all carbon-fibre-reinforced-plastic telescope with internal star trackers and has one fixed channel at 119 GHz and four receivers in the 490– 580 GHz range, each tuneable over 17 GHz . The Schottky mixers, the 119 GHz preamplifier and the low-noise IF amplifiers are cooled by a closed cycle Stirling cooler to about 140 K . The signals are processed by one acousto-optical spectrometer and two autocorrelation spectrometers, stored on board and sent to ground. Odin, the receiver system, testing and the in-orbit operation will be described together with results. Odin was developed by SSC in collaboration with space agencies and institutes in Sweden, France, Canada and Finland.

Eight-Channel 77-GHz Front-End Module With High-Performance Synthesized Signal Generator for FM-CW Sensor Applications

This paper presents a new frequency-modulated continuous-wave front-end module intended to serve next-generation automotive radar sensors. Providing one transmit and eight receive channels, the module is designed to operate between a multibeam antenna and an advanced signal-processing unit. All receive channels are equipped with low-noise amplifiers, mixers for downconversion, and IF amplifiers. Cascaded buffer amplifiers for the local-oscillator signal enable parallel operation of all receive channels. A high-performance synthesizer provides generation and transmission of arbitrarily programmable frequency ramped waveforms with high stability and linearity. Slope and frequency deviation of the waveforms can be adjusted for the respective radar application. Short settling times of the synthesizer allow very fast slopes and, thus, short distance measurements. An overview of the overall front-end module design and realization approach is given, including a more detailed description of the synthesizer concept. All active millimeter-wave functions are realized with GaAs monolithic microwave integrated circuits assembled in a hermetically sealed multichip module (MCM). The MCM itself is incorporated into a three-layer printed-circuit-board stack onto which IF amplification, frequency control, waveform generation as well as dc and bias control is realized. A summary of the measured performance data obtained from correspondingly built-up prototypes is given.

Nonlinear Analysis of Noise in Current-Steering Variable Gain Amplifiers

This paper investigates the difference between the small-signal noise figure and the noise figure in the presence of a large signal at the input of a current-steering variable gain pair. The mechanism of noise generation in the presence of a large signal at the emitters of the current-steering pair is analyzed for single-ended and differential operation. An analytical equation for the large-signal noise figure is derived. The results are applied to a cable TV IF amplifier and compared to measured data.

A low-power 200-mhz receiver for wireless hearing aid devices

The design of a low-power receiver for a wireless hearing aid system working in the 174-223-MHz range and its implementation in a 0.8-μm BiCMOS technology is shown. The chip comprises a low-noise amplifier, an RF mixer, a variable-gain IF amplifier, and a demodulator. The latter consists of a digital phase shifter and I/Q IF mixers, fifth-order Bessel filters, and dc amplifiers. Measurements demonstrate that merely 667 μA is consumed for the reception of an 8-ary phase-shift keying signal with a data rate of 336 kb/s. The receiver works with different modulation formats, including those carrying information in the amplitude.

A broadband dc SQUID based rf amplifier: experimental basics and development concept

We present a concept of a broadband IF amplifier based on experimental results obtained with a dc SQUID rf amplifier (SQA). The frequency range is broadened by using several SQAs, each one tuned to its own central frequency at both input and output; the numerical simulations are presented. A possibility of fine adjustment of the input impedance is numerically demonstrated in the range of 1–1000 Ω. The following parameters are expected for a three-channel SQA: central frequency ≈4 GHz, bandwidth 1 GHz, noise temperature ≈2 K, input saturation ≈300 K GHz.

Design and testing of ECE radiometer for Sinp-Tokamak

A multi channel ECE Radiometer, in the frequency range of 75 - 110 GHz, has been designed, constructed and tested for the SINP-Tokamak to diagnose second harmonic X-mode electron cyclotron emission (ECE). This frequency range covers approximately 80% of the plasma cross section in case of a magnetic eld of B = 1.5 T. For the maximum field of the SINP-Tokamak B = 2.0 T, about 50% is covered. The ECE radiation is received by a single horn antenna with a gain of approximately 30 dB. To increase the spatial resolution perpendicular to the line of sight, a focusing lens is employed. The incoming radiation power is split into two branches by a 3dB coupler. Before down conversion of the input spectrum, the upper and the lower side band are selected respectively by means of a high pass and a low pass filter. Behind the filters, identical components are employed. The local oscillator frequency is 92 GHz for both mixers. The IF frequency range after down conversion is 2 to 18 GHz. The IF spectrum is amplified by two amplifiers with a total gain of approximately 60 dB. The outputs of these amplifiers are split into 6 branches. The frequency selection is made by band pass filters and the received power is detected by Schottky diode detectors followed by video amplification and ltering. The data is recorded by an ADC with 1 MHz sampling rate. The radiometer has been tested and calibrated with a high temperature blackbody radiator. The effective input noise temperature for the radiometer channels is found to be in the order of 0.1 eV. The linear regime of operation extends up to an input power which corresponds to an electron temperature of approximately 200 eV. Above this temperature the 1 dB compression point of the Schottky diode detectors is exceeded and the IF gain should be reduced. This can be easily done by incorporating appropriate attenuator behind the IF amplifiers.

Broadband Amplifier Module Used in 3MM IF-Switch Radiometer

This paper introduced the design procedure of a low-noise broadband amplifier module used in 3mm IF-Switch radiometer. We first analyzed the impact of IF amplifier on the overall performance of the radiometer and then illustrated the techniques used in broadband amplifier design. CAD software was used in the procedure of simulation and the circuit was implemented in hybrid microstrip format. The final amplifier module matched well with the simulation result.

Analysis and optimization of a novel biasing for constant‐gain CMOS open‐loop amplifiers

AbstractA replica biasing circuit is presented which allows open‐loop gain in CMOS amplifiers to be accurately set. The proposed solution is a new biasing which takes advantage of a triode‐biased transistor instead of the ΔVGS approach which is the traditional one. The circuit can be applied to both RF and IF amplifiers which are based on resistive loads in order to achieve high‐frequency and/or low‐noise performance. A detailed analysis of second‐order effects is then given which emphasizes the effects due to mobility degradation, channel‐length modulation and threshold voltage mismatches. Simulated results show a good sensitivity to process variations. Copyright © 2001 John Wiley & Sons, Ltd.

A low-cost uniplanar sampling down-converter with internal local oscillator, pulse generator, and IF amplifier

In this paper, we report on the development of a new integrated-circuit sampling down-converter having its own pulse generator, local oscillator (LO), and IF amplifier. The internal pulse generator uses a step recovery diode together with a unique ultra-wide-band hybrid junction to generate sub-nanosecond balanced pulses for gating the sampling diodes. The down-converter exhibits a conversion gain from 12 to 15.5 dB over an RF frequency of 0.01-3 GHz with 10-MHz LO and sampling pulses of about 100 ps. Return loss at the RF port is better than 15 dB over this RF bandwidth. The down-converter exhibits a good linearity and low harmonic levels. This down-converter employs a coplanar waveguide and slot line to make the entire circuit uniplanar and is, thus, suitable for low-cost production. In addition, if has an internal pulse generator, LO, and IF amplifier, making it a compact receiver subsystem, which can readily be used in many microwave systems.

Analog MMICs for millimeter-wave applications based on a commercial 0.14-μm pHEMT technology

This paper describes recent results obtained from the monolithic-microwave integrated-circuit design activity at Chalmers University, Goteborg, Sweden. The goal is to design all circuits needed for the front end of a 60-GHz wireless local area network and to build various system demonstrators. Some recent experimental results from this activity like different 60-GHz amplifiers, a general-purpose IF amplifier, a 60-GHz resistive mixer, and frequency multipliers are reported in this paper. Parameters such as the gain, conversion loss, noise figure, dc-power dissipation, as well as the model used in the simulations are reported and discussed.

A 2.4-GHz low-IF receiver for wideband WLAN in 6-/spl mu/m CMOS-architecture and front-end

This paper presents the 2.4-GHz front-end and the first downconversion section of a fully integrated low-IF receiver. The dual-conversion receiver rejects the image repeatably by 60 dB using integrated polyphase filters without calibration or tuning. The gain of the RF mixer and IF amplifier is switchable to slide the available dynamic range of the following stages based on the conditions of the input signal. The front-end and downconversion sections drain 35 mA on average from a 3.3-V supply. Minimum cascade noise figure is 7.2 dB, and maximum cascade IIP3 is -3.4 dBm.

A 2.4 GHz low-IF receiver for wideband WLAN in 0.6μm CMOS

Abstract This paper presents the 2.4 GHz front-end and the first downconversion section of a fully integrated low-IF receiver. The dual-conversion receiver and rejects the image repeatably by 60 dB using integrated polyphase filters without calibration or tuning. The gain of the RF mixer and IF amplifier is switchable to slide the available dynamic range of the following stages, based on the conditions of the input signal. The front-end and downconversion sections drain 35 mA on average from a 3.3 V supply. Minimum cascade NF is 7.2 dB, and maximum cascade IIP3 is −3.4 dBm.

Low-voltage C-band Si BJT single-chip receiver MMIC based on Si 3D MMIC technology

This letter demonstrates a C-band Si BJT MMIC single-chip receiver based on the masterslice 3D MMIC technology. The fabricated receiver MMIC on a chip of 1.8 mm by 1.8 mm integrates a low-noise amplifier, an image-rejection mixer, and an IF hybrid associated with an IF amplifier. The fabricated components on the chip are designed by using reactive matching method due to both broadband and low-voltage operation. The receiver MMIC achieves a conversion gain of 13.5 dB, a noise figure of 5.2 dB, and an image rejection ratio of 30.6 dB at 5.2 GHz. This receiver also has a flat gain characteristic in the C-band. The power consumption of this MMIC is 115 mW with 2 V collector supply voltage.

Using Analog Predistortion for Linearizing Class A–C Power Amplifiers

An analog 5th order, complex-valued polynomial predistortion IC has been built to linearize the behavior of RF power amplifiers. The predistorter can be used either at baseband or low IF frequencies and it was tested using a simple IF amplifier that could be biased to operate in classes A, AB, B and C. Intermodulation products can be reduced by 20 to 30 dB in classes A and AB over a bandwidth of several MHz. In classes B and C the shape of nonlinearity is such that a low-order polynomial predistortion function is not sufficient for linearizing them.