Ultra-wideband RF Research Articles

Ultra-wideband GaN RF power amplifier based on low-pass ladder matching network

Ultra-wideband GaN RF power amplifier based on low-pass ladder matching network

A 0.5–15 GHz reconfigurable IR-UWB receiver in 28 nm CMOS

A 0.5–15 GHz ultra-wideband (UWB) RF reconfigurable receiver in UMC 28 nm CMOS used for IR-UWB (impulse radio UWB) radar system is proposed in this paper. This receiver employs a 0.5–8 GHz path and an 8–15 GHz path to achieve the wide frequency band, and we proposed an RF channel select voltage-to-time converter (VTC) circuit. Two different low noise amplifiers (LNAs) are adopted in the two paths to obtain the high performance of noise figure (NF) and gain. The common drain stage and resistance negative feedback technology as well as the source degeneration inductive technology are introduced to achieve a high flat gain and fine input matching. The R-2R variable load network of a programable gain amplifier (PGA) gives it a nearly 24 dB dynamic range and approximately linear gain control. A 500MS/s time domain analog to digital converter (TD-ADC) with an equivalent sampling rate of 16GS/s is shared for the two paths which can realize the direct RF sampling. The input RF signal path selection is implemented by configuring the Band_sel signal. The receiver has reconfigurability of the RF front end and better power consumption and area. In the frequency of 0.5–8 GHz, the S11 is below −7.9 dB and the NF is smaller than 6 dB. In the frequency of 8–15 GHz, the S11 is below −8dB and the NF is smaller than 11 dB. The receiver dissipates 242.72mW with an area of 1.01 mm2

Research and realization of 150W ultra-wideband reconfigurable RF power amplifier

Research and realization of 150W ultra-wideband reconfigurable RF power amplifier

Design of a 0.8-2.2GHz ultra-wideband RF high power amplifier

Based on the self-developed standard process RF-LDMOS device, a new ultra-wideband RF power amplifier is designed in this letter. The amplifier removes the absorbing resistor and capacitor series structure at the end of the drain. The stability of the circuit is enhanced by the pre-matching circuit. Considering the small impedance value of the RF high-power device, it is difficult to achieve broadband matching. The novel tapering drain transmission has been developed which overcomes the distributed amplifier’s limitations of low power and efficiency. Ultra-wideband RF amplifier has excellent output power and efficiency. The measurement results show that from 0.8-2.2GHz, under the condition of 28V power supply, the saturated output power is 43dBm (20W), the power gain is 10dB, the drain efficiency is about 30%-50%; The peak-to-average ratio is 8dB, and the ACPR is less than -41dBc when the linear output is 5W, proving the effectiveness of the new tapered drain structure to achieve broadband.

Hardware Implementation and RF High-Fidelity Modeling and Simulation of Compressive Sensing Based 2D Angle-of-Arrival Measurement System for 2-18 GHz Radar Electronic Support Measures.

This article presents the hardware implementation and a behavioral model-based RF system modeling and simulation (M&S) study of compressive sensing (CS) based 2D angle-of-arrival (AoA) measurement system for 2–18 GHz radar electronic support measures (RESM). A 6-channel ultra-wideband RF digital receiver was first developed using a PXIe-based multi-channel digital receiver paired with a 6-element random-spaced 2D cavity-backed-spiral-antenna array. Then the system was tested in an open lab environment. The measurement results showed that the system can measure AoA of impinging signals from 2–18 (GHz) with overall RMSE of estimation at 3.60, 2.74, 1.16, 0.67 and 0.56 (deg) in L, S, C, X and Ku bands, respectively. After that, using the RF high-fidelity M&S (RF HF-M&S) approach, a 6-channel AoA measurement system behavioral model was also developed and studied using a radar electronic warfare (REW) engagement scenario. The simulation result showed that the airborne AoA measurement system could successfully measure an S-band ground-based target acquisition radar signal in the dynamic REW environment. Using the RF HF-M&S model, the applicability of the system in other frequencies within 2–18 (GHz) was also studied. The simulation results demonstrated that the airborne AoA measurement system can be used for 2–18 GHz RESM applications.

Photonics for Ultrawideband RF Spectral Analysis in Electronic Warfare Applications

Electronic warfare receivers must satisfy particularly demanding requirements, and current electronic solutions must find a tradeoff between the request for high performance (in particular, very wide bandwidth, very high sensitivity, and very linear response) and the need for light and small systems. Photonics has been often proposed as a potential enabler of performance improvements, thanks to its wide tunability and precision, and recently the advancements of the photonic integration technologies are also promising strong reductions of size and weight. In this paper, we present an overview of the photonics-based solutions proposed so far in the field of electronic warfare. In particular, we focus on the specific implementation of a spectrum scanner we have recently proposed. Besides the performance in terms of bandwidth, linearity, and sensitivity, which are on par with the state-of-the-art electronic commercial systems, here, we report on our last advancements in terms of tuning speed. Further improvements are also discussed, in terms of both tuning speed and integrability.

A UWB solution for wireless intra‐spacecraft transmissions of sensor and SpaceWire data

SummaryThis paper presents the design, testing, and validation of a ultra‐wideband (UWB) wireless solution to replace wired intra‐spacecraft communications with wireless communications. The system requirements are provided in the framework of the Eu:CROPIS mission and the wired intra‐spacecraft communication system is replaced with a two‐segment wireless network. As such, distinct sets of UWB gateways and nodes are prototyped to interface with the on‐board entities and properly handle the data transmission in the resulting spacecraft and payload wireless networks. To accomplish these tasks, a custom radio module integrated into the prototypes was designed to provide the appropriate UWB RF front‐end and run a custom‐built communication stack. The viability of the solution was tested in laboratory conditions. For the test scenarios, sensor data are acquired in the payload network and forwarded as SpaceWire packets over the spacecraft network. Experimental test results indicate the suitability of the proposed solution in terms of delay and data integrity for implementing intra‐spacecraft wireless communications.

Microwave Photonic Channelizer Based on Polarization Multiplexing and Photonic Dual Output Image Reject Mixer

Microwave photonic channelizer based on coherent frequency combs (OFCs) enables processing of ultra-wideband RF signals using low-frequency components. The channel number usually equals to the comb line number of the OFCs and the bandwidth for the microwave input is determined by the frequency spacing of the OFCs. However, the generation of coherent OFCs with large comb lines and large frequency spacing is extremely challenging, limiting greatly the potential of the OFC-based channelizer. In this paper, a microwave photonic channelizer based on polarization multiplexing and photonic dual output image reject mixing is proposed and demonstrated. A broadband signal can be divided into 8 channels using only one optical carrier and a pair of dual-polarization local oscillators (DP-LOs). Each DP-LO has only 2 spectral lines with orthogonal polarization states. In addition, by introducing a pair of OFCs with $N$ comb lines, $8N$ channels can be output. The requirement of the comb line number is efficiently reduced, and the in-band interference is greatly suppressed by introducing the polarization multiplexing and the photonic dual-output image-reject mixing. A proof-of-concept experiment is carried out. An RF signal with 9.6-GHz bandwidth centered at 14 GHz is successfully divided into 8 channels with 1.2-GHz bandwidth, and the in-band interference is effectively suppressed for each channel. In addition, RF signals with 2.4-GHz bandwidth centered at 24.8 and 30.8 GHz are also successfully channelized, respectively.

Application of ultra wideband RF energy harvesting by using multisection Wilkinson power combiner

In this study, an ultra-wide band (UWB) energy harvesting circuit was proposed using the Greinacher rectifier circuit. The circuit was designed with Wilkinson power combiner (WPC) for use at two different radio frequency signal inputs. To enable broadband operation, the multisection Chebyshev impedance matching technique was applied in the branches of the WPC circuit. The center frequency was selected 2.2 GHz in the design. In terms of the parameters of reflection, transmission and isolation, the WPC circuit operates in the 0.4 GHz-3.4 GHz range and the percentage bandwidth has been calculated as 136%. In the designed Greinacher rectifier circuit, power conversion efficiency (PCE) was analyzed for different input powers. When load resistor selected as R = 1500 Ω, the PCE for the input power of 9 dBm was about 70%. The proposed circuit, where WPC and Greinacher rectifier circuits was used together for energy harvesting; was operated in the frequency ranges BW1 = 0.4-0.81 GHz, BW2 = 1.54-1.84 GHz, and BW3 = 2.2 GHz-2.89 GHz. As a power combining application, dual power inputs were applied to the WPC circuit with frequencies of 540 MHz-1800 MHz, 540 MHz-2450 MHz, 540 MHz-2700 MHz, 800 MHz-1800 MHz, 800 MHz-2450 MHz and 800 MHz-2700 MHz. Eventually, approximately 70.5% PCE and 1.65 V output voltage were obtained.

SLATS

As the density of wireless, resource-constrained sensors grows, so does the need to choreograph their actions across both time and space. Recent advances in ultra-wideband RF communication have enabled accurate packet timestamping, which can be used to precisely synchronize time. Location may be further estimated by timing signal propagation, but this requires additional communication overhead to mitigate the effect of relative clock drift. This additional communication lowers overall channel efficiency and increases energy consumption. This article describes a novel approach to simultaneously localizing and time synchronizing networked mobile devices. An Extended Kalman Filter is used to estimate all devices’ positions and clock errors, and packet timestamps serve as measurements that constrain time and overall network geometry. By inspection of the uncertainty in our state estimate, we can adapt the number of messages sent in each communication round to balance accuracy with communication cost. This reduces communication overhead, which decreases channel congestion and power consumption compared to traditional time of arrival and time difference of arrival localization techniques. We demonstrate the performance and efficiency of our approach using a real network of custom RF devices and mobile quadrotors.

Harmonium

We introduce Harmonium , a novel ultra wideband (UWB) RF localization architecture that achieves decimeter-scale accuracy indoors. Harmonium strikes a balance between tag simplicity and processing complexity to provide fast and accurate indoor location estimates. Harmonium uses only commodity components and consists of a small, inexpensive, lightweight, and FCC-compliant UWB transmitter or tag , fixed infrastructure anchors with known locations, and centralized processing that calculates the tag’s position. Anchors employ a new frequency-stepped narrowband receiver architecture that rejects narrowband interferers and extracts high-resolution timing information without the cost or complexity of traditional UWB approaches. In a complex indoor environment, 90% of position estimates obtained with Harmonium exhibit less than 31 cm of error with an average of 9 cm of inter-sample noise. In non-line-of-sight conditions (i.e., through-wall), 90% of position error is less than 42 cm. The tag draws 75 mW when actively transmitting, or 3.9 mJ per location fix at the 19 Hz update rate. Tags weigh 3 g and cost $4.50 USD at modest volumes. Furthermore, VLSI-based design concepts are identified for a simple, low-power realization of the Harmonium tag to offer a roadmap for the realization of Harmonium concepts in future integrated systems. Harmonium introduces a new design point for indoor localization and enables localization of small, fast objects such as micro quadrotors, devices previously restricted to expensive optical motion capture systems.

Thermal and dynamic range characterization of a photonics-based RF amplifier

This work reports a thermal and dynamic range characterization of an ultra-wideband photonics-based RF amplifier for microwave and mm-waves future 5G optical-wireless networks. The proposed technology applies the four-wave mixing nonlinear effect to provide RF amplification in analog and digital radio-over-fiber systems. The experimental analysis from 300 kHz to 50 GHz takes into account different figures of merit, such as RF gain, spurious-free dynamic range and RF output power stability as a function of temperature. The thermal characterization from -10 to +70 °C demonstrates a 27 dB flat photonics-assisted RF gain over the entire frequency range under real operational conditions of a base station for illustrating the feasibility of the photonics-assisted RF amplifier for 5G networks.

Ultra-Wideband Low-Loss Switch Design in High-Resistivity Trap-Rich SOI With Enhanced Channel Mobility

In this paper, the stress memorization technique (SMT) effects upon ultra-wideband RF switch performance are investigated for the first time. Low insertion loss (IL), high isolation, ultra-wideband (dc to 50 GHz) single-pole double-throw (SPDT), and single-pole four-throw (SP4T) switches designed with commercial 0.13- $\mu \text{m}$ high-resistivity (HR) trap-rich SOI technology with/without SMT are presented and investigated. 2.5 V nMOS transistor ( $L_{g} = 0.2~\mu \text{m}$ ) with low $R_{\mathrm{\scriptscriptstyle ON}} {^\ast} C_{\mathrm{\scriptscriptstyle OFF}}$ from GF 130RFSOI PDK is used. It is found that channel mobility of switch transistor is improved by SMT and thus switch performance can be further improved. Moreover, the impact of transistor channel length, which has dominant effects on both IL and isolation of the switches, under different gate bias on switch performance are also studied and verified experimentally. Low measured IL of less than 2.1 dB and good isolation of better than 27 dB from dc to 50 GHz are obtained for the SPDT switch. For SP4T switch, the measured IL of less than 2.6 dB and isolation of better than 27 dB are achieved from dc to 35 GHz. The active chip areas of designed SPDT and SP4T switches are compact with size of only $0.214 \times 0.19~\text {mm}^{2}$ and $0.36 \times 0.19~ \text {mm}^{2}$ , respectively.

A fully integrated W‐band pulse compression radar CMOS transceiver

AbstractA fully integrated ultra‐wideband (UWB) W‐band pulse compression radar transceiver in a 65‐nm CMOS technology is presented. The transceiver adopts a pulse compression scheme for high power spectral density with low TX leakage. Two identical voltage controlled oscillators, which are coupled through the second harmonic, are designed to achieve high output power and low phase noise without buffers. A transformer‐based local oscillator distribution network is proposed to achieve both small chip area and high port‐to‐port isolation. The transceiver chip produces 7.5‐GHz UWB RF pulses with 14.5‐dBm peak output power in the tuning range of 75–81 GHz, while the receiver shows a dynamic range of above 60 dB. The radar module was realized with waveguide transitions from a micro‐strip to a WR‐10 waveguide, and was capable of differentiating two targets with 6.5‐cm separation within 30 m distance.

An Ultra Wideband, Novel and Reliable RF MEMS Switch

This paper presents the design and characterization of wide band ohmic microswitch with an actuation voltage as low as 20~25 V, and a restoring force of 14.1 μN. The design of the proposed switch is primarily composed of an electrostatic actuator, bridge membrane, cantilever (beam) and coplanar waveguide, suspended over the substrate. The analysis shows an insertion loss of −0.002 dB at 1GHz and remains as low as −0.35 dB, even at 100 GHz. The isolation loss of the switch is sustained at −21.09 dB at 100GHz, with a peak value of −99.58 dB at 1 GHz and up-state capacitance of 4 fF. To our knowledge, this is the first demonstration of a series contact switch, which works over a wide bandwidth (DC-100 GHz) and with such a high and sustained isolation, even at high frequencies and with an excellent figure of merit (f_c=1/2.pi.Ron.Cu= 39.7 THz).

Towards development of a mobile RF Doppler sensor for continuous heart rate variability and blood pressure monitoring.

The standard in noninvasive blood pressure (BP) measurement is an inflatable cuff device based on the oscillometric method, which poses several practical challenges for continuous BP monitoring. Here, we present a novel ultra-wide band RF Doppler radar sensor for next-generation mobile interface for the purpose of characterizing fluid flow speeds, and for ultimately measuring cuffless blood flow in the human wrist. The system takes advantage of the 7.1~10.5 GHz ultra-wide band signals which can reduce transceiver complexity and power consumption overhead. Moreover, results obtained from hardware development, antenna design and human wrist modeling, and subsequent phantom development are reported. Our comprehensive lab bench system setup with a peristaltic pump was capable of characterizing various speed flow components during a linear velocity sweep of 5~62 cm/s. The sensor holds potential for providing estimates of heart rate and blood pressure.

A 79-GHz Adaptive-Gain and Low-Noise UWB Radar Receiver Front-End in 65-nm CMOS

A 79-GHz adaptive-gain and low-noise ultra-wideband radar receiver RF front-end integrated circuit in 65-nm CMOS is presented in this paper. The receiver consists of an adaptive-gain low-noise amplifier (AGLNA) and a ${ g}_{ m}$ -boosted sub-harmonic mixer (SHM). The proposed AGLNA controls the gain with adaptive biased circuits, which lowers the gain as the received signal power increases to provide wide dynamic range to the radar receiver without any external controls. We analyzed the input impedance of a cascode amplifier with a parallel resonant inductor, which improves the noise figure. The proposed ${ g}_{ m}$ -boosted SHM uses a transformer-based feedback network with NMOS bleeding circuits to provide a high conversion gain. The SHM was designed to use a differential local oscillator (LO) signal to have a simple structure and operate at low LO power. The measured conversion gain range was from 16 to $-{\hbox{7.5 dB}}$ with a received power range from $-{\hbox{45}}$ to $-{\hbox{5 dBm}}$ at 79.5 GHz. The measured noise figure was 10.5 dB and the measured 2LO-to-RF isolation was 70 dB. The chip area is ${\hbox{0.47}}\times {\hbox{1.23}}~{\hbox{mm}}^{2}$ .

Precision Broadband RF Signal Recovery in Subsampled Analog Optical Links

We present a novel technique for ultrawideband RF disambiguation where we are able to determine the precise Nyquist band from which an optically sampled, and therefore downconverted signal originated. This is accomplished by applying a discrete perturbation to the sampling rate, and measuring the magnitude and direction of the shift in signal location within the fundamental Nyquist band. Once the Nyquist band has been determined, the exact signal frequency can also be recovered. We demonstrate extremely accurate multioctave signal recovery over 1 MHz-40 GHz.

An UWB LNA Design with PSO Using Support Vector Microstrip Line Model

A rigorous and novel design procedure is constituted for an ultra-wideband (UWB) low noise amplifier (LNA) by exploiting the 3D electromagnetic simulator based support vector regression machine (SVRM) microstrip line model. First of all, in order to design input and output matching circuits (IMC-OMC), sourceZSand loadZLtermination impedance of matching circuit, which are necessary to obtain required input VSWR (Vireq), noise (Freq), and gain (GTreq), are determined using performance characterisation of employed transistor, NE3512S02, between 3 and 8 GHz frequencies. After the determination of the termination impedance, to provide this impedance with IMC and OMC, dimensions of microstrip lines are obtained with simple, derivative-free, easily implemented algorithm Particle Swarm Optimization (PSO). In the optimization of matching circuits, highly accurate and fast SVRM model of microstrip line is used instead of analytical formulations. ADCH-80a is used to provide ultra-wideband RF choking in DC bias. During the design process, it is aimed thatVireq= 1.85,Freq=Fmin, andGTreq=GTmaxall over operating frequency band. Measurements taken from the realized LNA demonstrate the success of this approximation over the band.

Ultrawideband RF Photonic Phase Shifter Using Two Cascaded Polarization Modulators

An ultrawideband RF photonic phase shifter implemented using two cascaded polarization modulators (PolMs) is proposed and experimentally demonstrated. The first PolM (PolM1) is employed to generate an optical carrier and two first-order sidebands that are orthogonally polarized. By aligning the polarization directions of the optical carrier and the two first-order sidebands from the first PolM with the two principal axes of the second PolM (PolM2), complementary phase modulation on the optical carrier and the first-order sidebands is produced if a DC voltage is applied to the second PolM. By selecting the optical carrier and one sideband using an optical filter and beating them at a photodetector, an RF signal with its phase that is tunable by tuning the applied DC voltage is generated. The proposed phase shifter has the advantages of fast tuning and an ultrawide frequency tunable range. An experiment is performed. A full 360° phase shift over an ultrawide frequency range from 5 to 40 GHz is demonstrated. The spurious free dynamic range of the phase shifter is also studied.