Frequency Mixer Research Articles

Analysis of a passive frequency mixer with current control by using protective intervals of heterodyne signals

A generalized technique for analyzing a current-controlled passive frequency mixer circuit using guard intervals between adjacent heterodyne signal pulses is proposed. The results of calculations and simulations in the Micro-Cap environment are presented for two cases of mixer input impedance: RLC circuit, RC circuit. The dependences of the modulus of the transfer impedance of the mixer for various durations of protective intervals are considered.

Lightwave-electronic harmonic frequency mixing.

Electronic frequency mixers are fundamental building blocks of electronic systems. Harmonic frequency mixing in particular enables broadband electromagnetic signal analysis across octaves of spectrum using a single local oscillator. However, conventional harmonic frequency mixers do not operate beyond hundreds of gigahertz to a few terahertz. If extended to the petahertz scale in a compact and scalable form, harmonic mixers would enable field-resolved optical signal analysis spanning octaves of spectra in a monolithic device without the need for frequency conversion using nonlinear crystals. Here, we demonstrate lightwave-electronic harmonic frequency mixing beyond 0.350 PHz using plasmonic nanoantennas. We demonstrate that the mixing process enables complete, field-resolved detection of spectral content far outside that of the local oscillator, greatly extending the range of detectable frequencies compared to conventional heterodyning techniques. Our work has important implications for applications where optical signals of interest exhibit coherent femtosecond-scale dynamics spanning multiple harmonics.

SC-CNTs: Thin Film Transistors for High-Performance, Low-Power, Flexible Electronics

Single Walled Carbon Nanotubes (SWNTs) have gained a great deal of media attention over the past almost-two decades. From their theoretical usage as the foundational material for space elevators that would take travelers beyond earth’s atmosphere, to an active material that would allow engineers to create nanobots that internally repair or treat the human body, applications for SWNTs are numerous and have resonated within the imagination of scientists and the media alike. Fast forwarding to the modern era, we find that nanotubes still have a great deal of technological promise, some of which parallel those usages that were theoretically conceived many years ago.For over a decade, NanoIntegris Technologies Inc. has been at the forefront of synthesizing high-purity, electronically enriched SWNT’s and, during that time, has found that our materials have proven to transcend from the theoretical to practical-usage realm. With over 1,900 publications citing the usage of NanoIntegris’ high performance materials, we have not only seen the beneficial properties of our materials studied via techniques such as scanning electron microscopy but have also received many positive use-cases for our materials such as being an additive of highly-conductive, electrode (anode/ cathode) slurries of next-generation lithium-ion batteries, to being used as an active for the highly-sensitive detection of COVID antigens.Within my talk, I will display the usage of our high-purity semiconducting (≥99%) single walled carbon nanotubes to make the next generation of high-performance electronics. I will focus upon the usage of our IsoSol-S100 semiconducting solution that served as the spin-coated semiconducting layer within a short channel (<10 µm) thin film transistor with ON/OFF of 104, a device thickness of 400 nm, and a mobility of 39 cm2V-1s-1. I will further discuss the usage of our IsoNanotubes-S 99% solution to serve as the active material within a low-power, wearable Radio Frequency biosensor that covers the GSM spectra, with an operation frequency up to 2.1GHz, and that can serve as both a frequency multiplier and mixer.

IP2 optimization in frequency mixers using ferroelectric field-effect transistors

Ferroelectric devices have traditionally been utilized in memory circuits due to their ability to retain a polarization charge and potentially act as a nonvolatile storage device. Their usage in applications unrelated to memory has also previously expanded into other digital and analog circuits, and now, it is being investigated in radio frequency circuits. This work explores the implementation of a frequency mixer using ferroelectric field-effect transistors in order to demonstrate stability against voltage offsets in a single-balanced mixer, making use of the polarization in the switching transistors to improve the performance of the second-order intermodulation product.

A mixer architecture using GaN-based split-gate nanowire transistor

Frequency mixer is an essential block in radio-frequency signal processing for frequency translation and phase comparison. The most common mixers are fabricated using passive elements which suffer from significant conversion loss and low isolation. Mixers using active devices are used less frequently and rather less matured on GaN technology. Here, we demonstrate a mixer based on GaN split-gate nanowire transistor, allowing low conversion loss and high isolation. A constriction is formed by electrostatic modulation of the effective gate width. The threshold voltage of the transistor is modified by one of the gate voltages through the width variation, while the other gate voltage biases the transistor in the saturation region. The nonlinear dependency of the transistor characteristics on the two gate voltages facilitates frequency translation. The mixing characteristics of this architecture are verified both experimentally and theoretically. The output power spectral density peaks at the difference frequency with a minimal conversion loss. Extremely high isolation is measured using three-port S-parameter measurements. The proposed architecture shows multiple benefits, additionally facilitating monolithic mixers on the GaN platform.

Multi-functional metasurface as a transmissive/reflective FSS and an on-air frequency mixer

In this paper, a multi-functional metasurface is proposed, which can work as a narrowband transmissive/reflective frequency selective surface (FSS) and an on-air frequency mixer based on its switching response. The metasurface is made up of unit cells with square and circular metallic loops connected by PIN diodes controlled by a bias source. In contrast to typical wideband FSSs, the structure provides 0.55 GHz of narrow stopband (a fractional bandwidth of 22%) at 2 GHz in the OFF state bias. The bandstop response can be adjusted by varying the reverse bias voltage. The metasurface alternates between its functionalities when in forward bias by providing a passband at the operational frequency. The structure is compact and operates as a transmissive/reflective surface under two different bias conditions (ON and OFF). The design is angularly stable and polarization-insensitive for both TE and TM polarisation. A prototype of the designed structure is developed and the measured results correlate well with the simulated responses from the finite-difference time-domain (FDTD) method-based simulation of the circuit model. On-air frequency mixing for a wave propagating through the metasurface is demonstrated and the effects of different parameters affecting the mixing are parametrically studied through FDTD simulations and experiments.

Gain measurement of microwave antenna with heterodyne bichromatic excitation in Rydberg atoms.

We propose a scheme for gain measurement of microwave (MW) antenna with heterodyne bichromatic excitation in Rydberg atoms via electromagnetically induced transparency (EIT). The Rydberg-EIT atoms serve as a frequency mixer with a strong locally oscillating MW field and a weak signal field. A large dispersion appears in the EIT windows due to the interference of two sub-EIT systems, which much narrows the transmission spectrum. The locally oscillating MW field could enhance the atomic response to the weak MW signals. The simulation results show that the gain measurement of MW antenna remains good accuracy even for weak MW fields and the minimum detectable MW field strength is about 1/12 of that of common EIT scheme. Other influences on the gain measurement are also investigated.

Wireless power and information dual transfer system via magnetically coupled resonators

High-efficiency medium-range wireless power transfer using magnetically coupled resonators requires a wireless data link between the contactless coils to regulate power. Multiplexing the power transfer channel as the information channel is a cost-effective solution for the communication. However, existing technologies cannot transmit data across the medium-range magnetically coupled resonators channel without substantially affecting power transfer. Here we show a power-electronics-converters based wireless power and information dual transfer system in which the information signals are modulated on one dc side of the inverter/rectifier, and transmitted through a conventional medium-range wireless power transfer system, and then demodulated on the other dc side. Using the frequency mixer characteristic of the inverter/rectifier, information is modulated onto the sideband of the power carrier and transmitted through the medium-range channel. Finally, we prototyped a 6.78 MHz system capable of transferring 45 W power across a one-meter distance with 62% efficiency and 60 kb/s bitrate for half-duplex communication.

13…67 GHz Frequency Mixer

Introduction. The requirements for the performance of measuring devices, including their operating frequency, are constantly becoming stricter. This encourages the creation of wide-band microcircuits for application in microwave blocks of devices, such as vector network analyzers (VNA) and spectrum analyzers (SA). One of such microcircuits, used in the receiver system, is a frequency mixer. The operating range of the mixer determines the operating range of the measuring instrument. Aim. Research and development of an ultra-wideband integrated circuit for a 13…67 GHz frequency mixer based on the GaAs QSBD technology by Micran JSC. Materials and methods. An analysis of existing classic and modified circuit transformers used in mixers was conducted. A modification of the transformer circuit, which allowed a frequency range of 10…70 GHz to be achieved,was proposed. Based on the obtained transformer and GaAs diode technology of Micran JSC, a complete mixer topology was developed and produced. An electrodynamic analysis of the integrated circuit was carried out; measurements were performed using a VNA up to 67 GHz. Results. A wideband mixer with a frequency range of 10…67 GHz is developed. A circuit design is proposed based on a balanced circuit with modified transformers and an intermediate frequency output circuit. The calculated dependences and measurement results of the integrated circuit of the mixer are presented. The mixer exhibits a conversion loss of less than 10 dB in the range of 10…67 GHz. Conclusion. A new broadband transformer with a range of operating frequencies from 10 to 70 GHz was developed. On its basis, a mixer microcircuit was simulated and manufactured. This microcircuit can be used in the receiving and transmitting units of modern measuring instruments. In terms of its characteristics, the proposed microcircuit is an analog of the Marki Mikrowave MM1-1467L mixer.

A High Performance I/Q Zero-IF Mixer with IIP2 Calibration Technique in 45nm SOI CMOS

This paper presents a high performance I/Q zero intermediate frequency (IF) mixer with a second-order input intermodulation point (IIP2) calibration technique in 45nm SOI CMOS process. A behavioral model of the mixer is established to analyze the sources of the second-order intermodulation distortion (IMD2). Based on the analysis, a high accuracy load resistance modulation array is applied to achieve excellent IIP2 performance. The frequency of the local oscillator (LO) signal is 3.5GHz, while the RF input signal frequency range is 3.4GHz∼3.6GHz. Simulation results show that the proposed zero-IF mixer achieves a conversion gain of more than 9.2dB with the input 1dB compression point of -11.28dBm. Noise figure is about 16.9dB at 10kHz and lower than 11.6dB at the frequency above 1MHz. The IIP2 of the circuit is larger than 66dBm after the calibration, which increases more than 40dBm.

Infrared and visible image fusion via mixed-frequency hierarchical guided learning

Existing deep learning-based fusion methods usually model local information through convolution operation or global contexts via self-attention mechanism. This serial scheme discards the local features during globality modeling, or vice versa, which may generate limited fusion performance. To tackle this issue, we introduce a mixed-frequency hierarchical guided learning network, or FreqFuse for short. More specifically, we first design a parallel frequency mixer through a channel splitting mechanism, including max-pooling and self-attention paths, to learn both high and low-frequency information. The mixer can provide more comprehensive features within a wide frequency range compared with a single dependency. Second, we develop a dual-Transformer integration module to guide fusion progress. The assigned weights are calculated by cross-token and cross-channel Transformer, which are used to measure the activity levels of source images and preserve their modality characteristics in the intermediate fused features. On this basis, we build a hierarchical guidance decoder to reconstruct a final fusion image. The cross-scale mixed-frequency features are reused to gradually optimize the activity levels of different modality images, and promote the fused result to be highly informative and strongly characterized. We benchmark the proposed FreqFuse on different datasets, and experimental results demonstrate that it achieves impressive performance compared with other methods.

A Novel Microwave Nonreciprocal Isolator Based on Frequency Mixers

We propose a nonreciprocal microwave isolator realized using an electrical circuit with two frequency mixers. A phase shift between the mixers at the same frequency as the local oscillator (LO) frequency is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $</tex-math> </inline-formula> /4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+$</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m\pi $</tex-math> </inline-formula> /2, and the powers of LO applied to each mixer have a phase difference of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $</tex-math> </inline-formula> /4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+ $</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n\pi $</tex-math> </inline-formula> /2 (where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m$</tex-math> </inline-formula> are the arbitrary integers). The up-converted signals in the upper and lower sidebands at the first mixer are combined at the subsequent mixer, even if they have phase differences. Because each sideband is in-phase for one direction and out-of-phase for the other direction, the circuit principally functions as an isolator with broadband from near dc to LO frequency. An isolator using commercially available microwave components successfully demonstrated more than 17 dB of isolation across the 0.01–1.50-GHz band at an LO frequency of 2.30 GHz. An on-chip broadband isolator with positive gain can be realized using superconductor–insulator–superconductor mixers.

Frequency Domain Disentanglement for Arbitrary Neural Style Transfer

Arbitrary neural style transfer has been a popular research topic due to its rich application scenarios. Effective disentanglement of content and style is the critical factor for synthesizing an image with arbitrary style. The existing methods focus on disentangling feature representations of content and style in the spatial domain where the content and style components are innately entangled and difficult to be disentangled clearly. Therefore, these methods always suffer from low-quality results because of the sub-optimal disentanglement. To address such a challenge, this paper proposes the frequency mixer (FreMixer) module that disentangles and re-entangles the frequency spectrum of content and style components in the frequency domain. Since content and style components have different frequency-domain characteristics (frequency bands and frequency patterns), the FreMixer could well disentangle these two components. Based on the FreMixer module, we design a novel Frequency Domain Disentanglement (FDD) framework for arbitrary neural style transfer. Qualitative and quantitative experiments verify that the proposed method can render better stylized results compared to the state-of-the-art methods.

A 24.25–30 GHz radio frequency up‐down converter with harmonic distortions rejection for 5G millimeter wave radio channel emulator applications

AbstractIn this paper, a 24.25–30 GHz fully integrated radio frequency (RF) up‐down converter with harmonic distortions rejection for 5G millimeter wave radio channel emulator applications is proposed and implemented in a 0.1‐μm GaAs pseudomorphic high‐electron‐mobility transistor technology. The RF up‐down converter integrates a frequency doubling amplifier chain local oscillator, a harmonic suppression mixer, and three frequency selective filters for unwanted harmonics suppression. To prevent the unwanted harmonics from leaking into the RF band, a higher sideband and high‐intermediate frequency mixer core with harmonic suppression filters is proposed. With this method, the unwanted harmonics are well suppressed. To effectively reduce the chip area, a miniaturized Marchand Balun based on a folded structure is proposed. The measured results demonstrate good in‐band spectral purity with more than 70 dB suppression of unwanted harmonics. Benefit from the high‐side injection mixing scheme and harmonics suppression method, the presented up‐down converter achieves a dynamic power range of −100 to −5 dBm with a conversion loss of 10 dB. The implemented RF up‐down converter occupies only 0.9 × 2.7 mm2 in size, with a power consumption of 400 mW under 4‐V supply.

A Lightweight, Zero-Power Intermodulation Sensor Based on the Graphene Oscillator

Wireless sensor networks (WSNs) require a massive number of sensor nodes for data collection and storage, for which the power management and area efficiency of battery-powered sensors may be an issue. In this article, we propose and numerically study a fully passive and lightweight intermodulation sensor based on the reconfigurable graphene field-effect transistors (GFETs) oscillator and passive frequency mixer. The output frequency of the self-powered GFET-based oscillator can be sensitive to the surface doping effect caused by charged surface absorbates, reactive gases, contaminations, or aqueous solutions. In the intermodulation sensor, the low-frequency signals generated by GFET oscillator are mixed with the incident radio frequency (RF) waves, forming the retransmitted and the RF intermodulation signals. Since the intermodulation products do not mess up with the reception signal, the unwanted clutters, self-jamming, and interferences can be effectively suppressed. Our results show that the output frequency of the GFET oscillator can sensitively respond to charged molecules, and such information can be encoded in the backscatter intermodulation signal. We believe that our GFET-based intermodulation sensor may be beneficial for a variety of the Internet of Things (IoTs), remote sensing, and environment monitoring applications.

Dynamic Interference Suppression for TV White Space: the Case of Thailand

In this work, we study the problem of co-existence between the LTE (Long Term Evolution) and the Digital Terrestrial Television Broadcasting (DTTB) channel. There are three scenarios: co-channel, upper and lower adjacent channels. We use the broadcasted signal from channel 3 called ThaiPBS, the actual case of Thailand for our study where the standard of digital terrestrial television broadcasting is DVB-T2 adopting 8 MHz bandwidth, while the 5 MHz bandwidth of LTE is considered as the interference. We propose a dynamic interference suppression method for increasing spectrum usage by optimizing TV white space utilization and minimizing interference. This method adopts the protection ratio concept to suppress the LTE interference on TV receiver. We implement our proposed algorithm as an adaptive interference controller using a Radio Frequency (RF) attenuator and a Raspberry Pi board for our testbed hardware. We illustrate the effectiveness of our proposed algorithm by doing experiment using our testbed and assessing the quality of the received TV signal by adopting the Quality of Experience (QoE) assessment. In our testbed hardware, a Log Periodic antenna is used for receiving the DTTB signal, while an RF digital transmitter is used for generating a 5MHz bandwidth of LTE signal, an ultra-high frequency (UHF) mixer is used to combine both signals, then a field strength meter is used to monitor video picture quality and to analyze the spectrum. According to the experiment, our proposed method can reduce the perceived video distortion by at least 62.5% for co-channel and 87.5% for adjacent channel, while the spectrum usage is increased by 100%.

Filter-Free Photonic Microwave I/Q Modulator for Reconfigurable Frequency Mixing

We report a simple and novel scheme to achieve the reconfigurable frequency mixing based on a filter-free photonic microwave in-phase/quadrature (I/Q) modulator. With proper photodetection configuration, four microwave frequency mixing functions are expediently reconfigured in our system: single-ended mixing, balanced mixing, I/Q mixing and image-reject mixing. The employed crucial optical modulator is a dual-polarization dual-parallel Mach–Zehnder modulator (DPol-DPMZM) driven by in-phase and quadrature intermediate frequency (IF) and local oscillator (LO) signals. The generation and switching of frequency down- and up-conversion and different mixing functions depend on the main direct current (DC) biases of the two sub-DPMZMs, instead of using additional optical hybrid, wavelength division multiplexer (WDM) or two pairs of cascaded polarization controller (PC) and polarization beam splitter (PBS) in previous reports. Our demonstrated experiment shows that the reconfigurable frequency mixer has high mixing spur suppression, frequency tunability, and image rejection ratio (IRR) of over 35 dB. The proposed simple and multifunctional structure may bring a broad potential application in radar and communication systems.

Analysis of a Passive Current-Controlled Frequency Mixer

The paper presents a generalized technique for calculating a passive current-controlled frequency mixer at an arbitrary intermediate frequency, taking into account the complex input impedance of the current source and output load. The results of simulation in the Micro-Cap environment and comparison with thecalculation are presented. The frequency dependences of the transfer impedance are considered.

High-stability flexible radio frequency transistor and mixer based on ultrathin indium tin oxide channel

In this work, a high-performance flexible radio frequency transistor using an ultrathin indium tin oxide film channel based on a solution-cast thin polyimide substrate has been demonstrated. The 60 nm short channel transistor shows a record high cut-off frequency of 5 GHz and a maximum oscillation frequency of 11 GHz with high uniformity among 40 devices. The radio frequency characteristics under various bending conditions have been systematically studied under a bending radius of 5 mm for 10 000 times and a bending radius of 1 mm for 1000 times, showing excellent stability with only 20% decrease in the cut-off frequency. Furthermore, a flexible frequency mixer has also been demonstrated at 2.4 GHz with decent conversion gains.

Realizing symmetry-guaranteed pairs of bound states in the continuum in metasurfaces

Bound states in the continuum (BICs) have received significant attention for their ability to enhance light-matter interactions across a wide range of systems, including lasers, sensors, and frequency mixers. However, many applications require degenerate or nearly degenerate high-quality factor (Q) modes, such as spontaneous parametric down conversion, non-linear four-wave mixing, and intra-cavity difference frequency mixing for terahertz generation. Previously, degenerate pairs of bound states in the continuum (BICs) have been created by fine-tuning the structure to engineer the degeneracy, yielding BICs that respond unpredictably to structure imperfections and material variations. Instead, using a group theoretic approach, we present a design paradigm based on six-fold rotational symmetry (C6) for creating degenerate pairs of symmetry-protected BICs, whose frequency splitting and Q-factors can be independently and predictably controlled, yielding a complete design phase space. Using a combination of resonator and lattice deformations in silicon metasurfaces, we experimentally demonstrate the ability to tune mode spacing from 2 nm to 110 nm while simultaneously controlling Q-factor.