Conversion Gain Of Mixer Research Articles

Quadrature amplitude modulation frequency up- and down-conversions using a positive-intrinsic-negative photodiode sampling mixer

Simulation and experimental performance analysis of a positive-intrinsic-negative photodiode (PIN-PD) sampling mixer used as frequency up and down-converters are presented. Besides, a frequency mixing with a PIN-PD can operate in a frequency range up to 47.3 GHz for up-conversion and 38.5 GHz for down-conversion. The design and operating regime peculiarities of a PIN-PD as an up and down-converter in a radio over fiber (RoF) system are also discussed. The conversion gain of a PIN-PD sampling mixer is simulated and measured. We showed that the gain may decrease from 27 dB at a mixing frequency of 8.3 GHz to 3 dB at the one with 47.3 GHz in an up-conversion mode and from 26.5 dB at 31.7 GHz to 7 dB at 38.5 GHz in a down-conversion mode, when the PIN-PD bias voltage was 0 V. The conversion gain degrades with the decrease of the bias voltage from 0 to −5 V. Error vector magnitudes (EVMs) of the quadratic amplitude modulation (M-QAM) up and down-converted signals are investigated. Quadrature phase shift keying (QPSK) data at bit rates between 312.5 Mbit / s and 5 Gbit / s are frequency-converted. The EVM is used a performance index to assess the mixing system. Exploitable EVMs in the range of 15% up to 34.9% are reached for up-conversion of the mixing frequency. For down-conversion, the EVM varies from 20% to 34.9% at 5 Gbit / s over the whole frequency range. The EVM of mixed signals is improved with 16-QAM and 64-QAM modulations.

A Dual-Band Receiver Based on a Single Superconducting Hot Electron Bolometer Mixer for DATE5 Telescope

Simultaneous multi-frequency observations can be of great advantage when line ratios need to be accurately determined. Five meters Dome A Terahertz Explorer (DATE5) telescope is proposed with two observation bands: 0.85 THz band and 1.35 THz band. In this paper, we report on a dual-band receiver based on a single quasi-optical superconducting hot-electron bolometer mixer. This novel concept allows simultaneous observation of the two bands for DATE5 telescope. Our measurement results show that the dual-band HEB receiver can simultaneously resolve the line spectra in both frequency bands. In particular, an RF tone has been observed with in single and dual frequency mode and the heterodyne performance of the HEB mixer has been compared. Although there is a reduction of mixer conversion gain, the available observation time can be improved by decreasing the time for source pointing and double-beam switching. Whats more, compared with conventional broadband receiver system, this novel technique can achieve compact system and provide a system redundancy for unattended observation.

Avoiding RF Isolators: Reflectionless Microwave Bandpass Filtering Components for Advanced RF Front Ends

RF/microwave bandpass filters (BPFs) are fundamental components in high-frequency RF transceivers. On the transmitter side, they limit the transmitted RF signal bandwidth by suppressing out-of-band spurious signals and intermodulation products, which are primarily generated by the nonlinear active stages and can affect other RF systems. On the other hand, in the receiver, they reject out-of-band interfering/jamming signals and noise. Whereas a large variety of microwave BPFs have been proposed in the technical literature for multiple technologies (e.g., [1] and [2]), most of these BPF devices achieve their filtering functionality by means of the frequency-selective power reflection processing of the RF input signal. This means that those RF signals allocated within the operational bandwidth of the BPF are transmitted to the output terminal (with some tolerable added in-band loss and reflective-type filter, hence decreasing the mixer conversion gain.

Design of RF Receiver Front end Subsystems with Low Noise Amplifier and Active Mixer for Intelligent Transportation Systems Application

This paper presents the design, simulation, and characterization of a novel low-noise amplifier (LNA) and active mixer for intelligent transportation system applications. A low noise amplifier is the key component of RF receiver systems. Design, simulation, and characterization of LNA have been performed to obtain the optimum value of noise figure, gain and reflection coefficient. Proposed LNA achieves measured voltage gains of ~18 dB, reflection coefficients of -20 dB, and noise figures of ~2 dB at 5.9 GHz, respectively. The active mixer is a better choice for a modern receiver system over a passive mixer. Key sight advanced design system in conjunction with the electromagnetic simulation tool, has been to obtain the optimal conversion gain and noise figure of the active mixer. The lower and upper resonant frequencies of mixer have been obtained at 2.45 GHz and 5.25 GHz, respectively. The measured conversion gains at lower and upper frequencies are 12 dB and 10.2 dB, respectively. The measured noise figures at lower and upper frequencies are 5.8 dB and 6.5 dB, respectively. The measured mixer interception point at lower and upper frequencies are 3.9 dBm and 4.2 dBm.

A 53–67 GHz Low-Noise Mixer-First Receiver Front-End in 65-nm CMOS

In this paper, we present a mixer-first receiver front-end suitable for millimeter wave (mm-wave) applications. The proposed architecture includes a modified single-balanced mixer core with an on-chip balun in order to provide a differential output from an injected single-ended local oscillator signal. The mm-wave active balun incorporates a cascode cross-coupled structure to achieve a high voltage gain with low amplitude and phase imbalance. The inter-stage inductors are utilized to increase the mixer conversion gain (CG). Moreover, by manipulating the transistor body effect in the transconductance stage, the CG and noise figure of the mixer are further improved. The mixer also achieves a high input return loss which makes it suitable for the mixer-first receivers. As a proof-of-concept, a 53–67 GHz mixer with a center intermediate-frequency of 20 GHz is designed and implemented in a 65-nm CMOS process. The mixer achieves a measured peak conversion gain of 12.1 dB and a 1-dB compression point of −5 dBm. Furthermore, the fabricated mixer achieves a minimum double-sideband (DSB) noise figure of 6.5 dB over its bandwidth. The whole chip consumes 11.5 mW from a 1-V supply and excluding the pads occupies 0.27 mm2 of silicon area.

Multi-Gate FinFET Mixer Variability Assessment Through Physics-Based Simulation

In this letter, we show that innovative physics-based simulations can be used for a comprehensive analysis of RF stages subject to random variations of technological parameters, including the computation of the average (deterministic) RF performance along with their statistical deviation. The variability analysis is addressed by means of the recently developed physics-based sensitivity analysis of AC parameters through Green’s functions. To demonstrate the technique, we address the analysis of a FinFET mixer exploiting an innovative independent gates topology, showing that a careful design allows to maximize the mixer conversion gain, while minimizing its variability versus several physical parameters, such as the gate length, oxide thickness, and fin width.

A 100–300-GHz Free-Space Scalar Network Analyzer Using Compact Tx and Rx Modules

This paper presents a 100–300-GHz quasi-optical network analyzer using compact transmitter and receiver modules. The transmitter includes a wideband double bow-tie slot antenna and employs a Schottky diode as a frequency harmonic multiplier. The receiver includes a similar antenna, a Schottky diode used as a subharmonic mixer, and an LO/IF diplexer. The 100–300-GHz RF signals are the 5th–11th harmonics generated by the frequency multiplier when an 18–27-GHz LO signal is applied. The measured transmitter conversion gain with $P_{\textrm {in}} = 18$ dBm is from −35 to −59 dB for the 5th–11th harmonic, respectively, and results in a transmitter EIRP from +3 to −20 dBm up to 300 GHz. The measured mixer conversion gain is from −30 to −47 dB at the 5th–11th harmonic, respectively. The system has a dynamic range > 60 dB at 200 GHz in a 100-Hz bandwidth for a transmit and receive system based on 12-mm lenses and spaced 60 cm from each other. Frequency-selective surfaces at 150 and 200 GHz are tested by the proposed design and their measured results agree with simulations. Application areas are low-cost scalar network analyzers for wideband quasi-optical 100 GHz–1 THz measurements.

All-Optical Radiofrequency Sampling Mixer Based on a Semiconductor Optical Amplifier Mach–Zehnder Interferometer Using a Standard and a Differential Configuration

An all-optical sampling based on a semiconductor optical amplifier Mach–Zehnder interferometer is performed. The frequency properties of a sampled signal are exploited to obtain both frequency up-conversion and frequency down-conversion of quadrature phase shift keying (QPSK) data. An optical pulse source, generating 10-ps-width pulses at a repetition rate of 7.8 GHz used as a sampling signal, allows operation in the range of 0.5–39.5 GHz. The conversion gain of the all-optical sampling mixer is measured over the whole frequency range. It varies over this range from 20.4 to 0 dB for frequency down-conversion and from 15.5 to −13.4 dB for frequency up-conversion. QPSK data at symbol rates between 8 and 128 MSymb/s are frequency converted. The Error Vector Magnitude is used to evaluate the quality of the frequency conversion. Exploitable error vector magnitudes (EVMs) in the range of 14% to 27.4% are reached for frequency up-conversion to the higher target frequency for all the symbol rates. For down-conversion, the EVM varies from 6.7% to 29.2% at the symbol rate of 64 MSymb/s for the whole frequency range. By using a differential configuration, the conversion gain is improved by 8.6 and 9 dB for up-conversion and down-conversion operations, respectively. The benefit provided by the differential configuration leads to a better EVM. Its value is shifted by almost 11% for frequency up-conversion and frequency down-conversion of data at a symbol rate of 64 MSymb/s.

Performance of the Caltech Submillimeter Observatory Dual-Color 180–720 GHz Balanced SIS Receivers

In this paper, we report on balanced SIS receivers covering the astronomical important 180-720 GHz submillimeter atmospheric window. To facilitate remote observations and automated spectral line surveys, fully synthesized local oscillators are employed. High-current-density Nb-AlN-Nb superconducting-insulating-superconducting (SIS) tunnel junctions are used as the mixing element. The measured double-sideband (DSB) 230 GHz receiver noise temperature, uncorrected for optics loss, ranges from 50 K at 185 GHz, 33 K at 246 GHz, to 51 K at 280 GHz. In this frequency range the mixer has a DSB conversion gain of 0 ±1.5 dB. The measured 460 GHz double-sideband receiver noise temperature, uncorrected for optics loss, is 32 K at 400 GHz, 34 K at 460 GHz, and 61 K at 520 GHz. Similar to the 230 GHz balanced mixer, the DSB mixer conversion gain is 1 ±1 dB. To help optimize performance, the mixer IF circuits and bias injection are entirely planar by design. Dual-frequency observation, by means of separating the incoming circular polarized electric field into two orthogonal components, is another important mode of operation offered by the new facility instrumentation. Instrumental stability is excellent supporting the LO noise cancellation properties of the balanced mixer configuration. In the spring of 2012 the dual-frequency 230/460 SIS receiver was successfully installed at Caltech Submillimeter Observatory (CSO), Mauna Kea, HI, USA.

Bias optimization of 2.4 GHz double gate MOSFET RF mixer

The optimum biasing points and structural design parameters for novel nano-scale double gate MOSFET (DG-MOSFET) radio frequency mixers are investigated at 2.4 GHz. Our objective is to analyze and identify the correlation of the conversion gain of the mixer circuit with the signal amplitude of the local oscillator (LO) as well as different device parameters, such as the gate length (L gate ), doping concentration (N A ) and body thickness (t Si ), thus minimizing signal loss and power consumption and increasing stability. The most important figure of merit is found to be the LO DC bias that determines the level of non-linearity in the transconductance response. Furthermore, we observe that in properly designed DG-MOSFETs $$(\hbox{L}_{gate} \ge 3t_{Si}),\; \hbox{L}_{gate}$$ ( L g a t e ? 3 t S i ) , L g a t e and N A have limited impact on the conversion gain of the mixer, while t Si has a more significant role to play. Although the mixing performance of DG-MOSFETs is ultimately limited by the short channel effects perpetrated by any given structural constraint, an optimum body thickness t Si exists in each case to maximize the conversion gain. Thus, we illustrate how 2D and quantum-corrected simulations can identify the optimum body thickness and optimum bias conditions in such compact nano-scale mixers.

A 12 GHz-Bandwidth CMOS Mixer With Variable Conversion Gain Capability

A broadband downconverter mixer using an operational transconductance amplifier (OTA) in the RF transconductor stage is presented in this paper. By changing the OTA's transconductance through a dc control voltage, the mixer's conversion gain is varied. Experimental results show that the mixer's conversion gain can vary from 17 dB down to 1.2 dB over a 12 GHz bandwidth. The maximum IP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> of the mixer is -3.7 dBm and its maximum IIP3 is + 8.6 dBm. Meanwhile, the maximum OP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1dB</sub> is +7 dBm and the maximum OIP3 is +21 dBm. The circuit consumes a maximum of 5.9 mW of power from a 1.2 V supply. The chip occupies an area of 0.105 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> excluding bonding pads.

Gain Expansion and Compression of SIS Mixers

It is a well known fact that SIS mixers exhibit gain compression when the output IF voltage swing becomes non-negligible compared to the width of the photon step. In this paper, we show that under certain circumstances, SIS mixers can also exhibit the inverse phenomenon-gain expansion. This non-linear behavior has been observed experimentally when the output power-voltage curve of an SIS mixer has a double peak feature over the photon step. In this case, if the device is biased at the valley position between the two peaks, the conversion gain of the mixer will increase with input signal power. Consequently, the noise temperature of the mixer deduced from a Y-factor measurement will be artificially reduced. Two different experimental methods have been used to characterize the linearity of SIS mixers. The accuracies of both methods are analysed.

A New Inductor-Less IP2 Enhancement Technique for CMOS Multi-Standard Mixer

The linearity and noise required by GSM and UMTS receivers make the design of a CMOS mixer for these applications so challenging. A new technique for IP2 improvement in Zero-IF active mixers is presented in this paper. This inductor-less technique is based on canceling the parasitic capacitor of common source node of the switching transistors and synthesizing resistive impedance. Using this technique, a reconfigurable down converter mixer works from 900MHz to 2.4 GHz is designed supporting GSM, DCS, PCS, UMTS and IEEE802.11 b-g standards. The mixer IIP2 is higher than 71 dBm in GSM and UMTS bands. The mixer conversion gain is higher that 12 dB in all frequency bands. The design is done in 65 nm CMOS technology and consumes 10mA from a 1.2V supply. The design meets the performance required for all mentioned standards, while its area and power is comparable with high performance single band mixers.

Gain Enhancement in Inductively-Loaded Distributed SIS Junction Arrays

Due to their very low IF output capacitance, series-connected distributed SIS junction array mixers possess very wide IF bandwidth. However, careful control of parasitic inductance in the IF network is important in order to obtain a flat IF response in this class of wideband mixer. We have studied the effect of inductive loading on the operation of these mixers, both experimentally and theoretically. It is shown that over the range of IF where the reactive part of the load impedance is large, a higher mixer conversion gain accompanied by a lower noise temperature is observed.

Study of the Effect of Microwave Radiation on the Operation of HEB Mixers in the Terahertz Frequency Range

We have investigated the effect of injecting microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the hot-electron bolometer mixer incorporated into a THz heterodyne receiver. More specifically, we show that exposing the mixer to microwave radiation does not cause a significant rise of the receiver noise temperature and fall of the mixer conversion gain so long as the microwave power is a small fraction of local oscillator power. The injection of a small, but controlled amount of microwave power therefore enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the gain stability of hot electron bolometer mixer receivers.

Effect of Magnetic Field on Performance of SIS Mixers Measured at 385–500 GHz

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

IF impedance and mixer gain of NbN hot electron bolometers

The intermediate frequency (IF) characteristics, the frequency dependent IF impedance, and the mixer conversion gain of a small area hot electron bolometer (HEB) have been measured and modeled. The device used is a twin slot antenna coupled NbN HEB mixer with a bridge area of 1×0.15μm2, and a critical temperature of 8.3K. In the experiment the local oscillator frequency was 1.300THz, and the (IF) 0.05–10GHz. We find that the measured data can be described in a self-consistent manner with a thin film model presented by Nebosis et al. [Proceedings of the Seventh International Symposium on Space Terahertz Technology, Charlottesville, VA, 1996 (unpublished), pp. 601–613], that is based on the two temperature electron-phonon heat balance equations of Perrin-Vanneste [J. Phys. (Paris) 48, 1311 (1987)]. From these results the thermal time constant, governing the gain bandwidth of HEB mixers, is observed to be a function of the electron-phonon scattering time, phonon escape time, and the electron temperature. From the developed theory the maximum predicted gain bandwidth for a NbN HEB is found to be 5.5–6GHz. In contrast, the gain bandwidth of the device under discussion was measured to be ∼2.3GHz which, consistent with the outlined theory, is attributed to a somewhat low critical temperature and nonoptimal film thickness (6nm).

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.

Linearity analysis and design optimisation for 0.18 μm CMOS RF mixer

Equations for the 1dB compression point and third-order intermodulation point as a function of circuit and technology parameters are derived using a Volterra series expansion. The linearity analysis for both single- and double-balanced CMOS Gilbert mixers is examined. The relation between the input third-order intercept point and source inductance is studied in depth. The gate to drain overlap capacitance, which is one of the dominant nonlinear elements in a MOSFET, is included in the model. The design methodology to satisfy the mixer noise figure and conversion gain while optimising linearity is summarized. The analytical predictions are verified with the Cadence SpectreRF circuit simulation and experimental data. Good agreement between the model predictions and experimental data is obtained.

Influence of the source inductance parasitic effect on the conversion gain of an HEMT gate mixer

This paper examines the influence of the presence of source inductance on the conversion gain of a gate mixer. Two effects are observed: degradation of the gain, and an increase of the local oscillator level power necessary to obtain the maximum gain. Nonlinear simulations, theoretical calculations, as well as experimental data demonstrate that these effects become more important in the millimeter-wave range. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 149–151, 1999.