Mm-wave Power Research Articles

Joint Beamforming and Power Splitting for Wideband Millimeter Wave SWIPT Systems

Simultaneous wireless information and power transfer (SWIPT) is a promising technology for enabling future internet-of-things applications particularly with battery-limited devices including autonomous vehicles, mobile robots, and distributed sensors. In recent years, there has been a growing interest in millimeter wave (mmWave) SWIPT because a wider energy coverage is provided by mmWave power transfer using a large antenna array than lower frequency solutions. However, research on mmWave SWIPT systems is lacking especially with practical hardware in spite of its importance. In particular, transmitter, information receivers, and nonlinear energy harvesters should be jointly designed under the constraints of transmit power and analog-digital hybrid beamforming structure. In this paper, we develop a joint design of transmit power allocation, beamforming, and receive power splitting for SWIPT downlink systems in wideband mmWave channel. The proposed scheme relies on the limited feedback of channel information. Also, the rate-energy region of the proposed mmWave SWIPT system is analyzed and the performance is verified by simulations.

A Wideband High-power Low-loss Power Divider Using Half-height Pin Gap Waveguide Technology

In this paper, for the first time, a wideband low -loss high-power equally splitting power divider based on the new half-height pin form is introduced with bandwidth from 10 to 13.5 GHz centered at 11.75 GHz. Also, for the first time, a wideband transition from coaxial line to half-height pin gap waveguide with no need of any matching sections with excellent results at the band of (10:20 GHz) was achieved. The proposed transition shows excellent return loss which is lower than 30 dB (measured) at the transition bandwidth center frequency which is (15 GHz) with 0.2 dB (measured) insertion loss and return loss lower than 20 dB (measured) with 0.55 dB insertion loss at the rest of the bandwidth. The proposed transition and power divider designs were validated using circuit and 3D full-wave simulations and confirmed using experimental measurements with all agreements. The power divider has simple manufacturing due to the new pin form; hence, it is suitable for low-cost mass production of high-power mm-wave power dividers.

A High-Power Broadband Multi-Primary DAT-Based Doherty Power Amplifier for mm-Wave 5G Applications

Silicon-based millimeter-wave (mm-Wave) power amplifiers (PAs) with high power and high peak/back-off efficiency are highly desired to efficiently amplify multi-Gb/s 5G NR signals. This article presents a fully integrated high-power broadband linear Doherty PA with multi-primary distributed-active-transformer (DAT) power combining. We introduce a transformer-based impedance inverter for active load modulation and a multi-primary DAT structure for hybrid series and parallel power combining. Based on this, we propose a transformer-based Doherty combiner with more design freedom and a multi-primary DAT-based Doherty PA for simultaneous active load modulation and low-loss power combining. The EM simulation results demonstrate that the proposed DAT-based Doherty output network achieves very symmetric and balanced load impedances among all the main and auxiliary PA ports. As a proof of concept, a 24-30-GHz prototype PA is implemented in a 0.13- μm SiGe BiCMOS process. The PA achieves 30.4% PAE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> , 28.3-dBm P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sat</sub> , 30.2% PAE at 26.8-dBm P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> , and 21.2% PAE at 6-dB back-off from P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sat</sub> at 28 GHz. Modulation measurement with single-carrier 64-QAM signals and 5G NR FR2 orthogonal frequency-division multiplexing (OFDM) signals has been demonstrated. For a 200-MHz 1-CC 5G NR FR2 64-QAM signal, the PA achieves 18.1-dBm P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">avg</sub> and 13.8% PAE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">avg</sub> with -25.1-dB rms EVM at 28 GHz.

Directed Graph Navigated Digital Predistortion of mmWave Power Amplifiers for 6G Hopping Applications

To exploit the limited communication resources, the real-time carrier frequency of the power amplifier (PA) may hop, which will result in rapid change in PA’s nonlinear behavior and bring huge challenge to make the digital predistortion (DPD) response in a timely manner. Different from the conventional methods that attempt to shorten the DPD updating time, a novel scheme of controlling its nonlinear variation is proposed. By analyzing PA’s various behaviors using graph model and extracting a directed graph to navigate its power adjustments, the variation in nonlinear behavior induced by hopping carrier frequency can be effectively compensated, which will mitigate the DPD performance deterioration when there is not enough time for DPD update. Finally, the proposed method was validated by experiments on a 100-MHz modulated signal stimulated millimeter-wave (mmWave) PA operating at five hopping carrier frequencies from 26.4 to 28 GHz, with the step of 400 MHz.

Modulation Index and Phase Imbalance of Dual-Sideband Optical Carrier Suppression (DSB-OCS) in Optical Millimeter-Wave System

This paper presents a Dual-sideband Optical Carrier Suppression (DSB-OCS) technique which is used to generate an optical millimeter-wave (mm-wave) signal in radio over fiber (RoF) systems. The proposed system employs a Dual-Electrode Mach-Zehnder Modulator (DE-MZM) and a carrier of 40 GHz mm-wave for data transmission through the RoF systems. Characteristics determining the performance of the system, among which are the modulation index, phase imbalance and dispersion parameters, are included. The performance evaluations of the system show that the mm-wave signal output power follows MZM’s transfer function when the modulation index is raised. Moreover, the generated optical mm-wave signal power is affected by phase imbalance and optical splitting ratio. It is observed that the optical fiber dispersion influences the DSB-OCS system by decreasing the amplitude of the mm-wave and the signal-to-noise ratio (SNR).

Performance Analysis of Millimeter Wave SWIPT System Using Ginibre Point Process

This paper deals with the coverage probability analysis of mmWave simultaneous wireless information and power transfer (SWIPT) system using stochastic geometry. mmWaves are higher frequency waves results in dense deployment of base stations (BS) leading to a higher data rate. Stochastic geometry provides a mathematical model to the randomly distributed nodes in the network. The Poisson point process (PPP) is the most analytically tractable and widely used model for the location of BSs, but it fails to capture the underlying separation between the BSs of cellular networks. Ginibre point process (GPP) model is used for the repulsion between the two nodes and provides a realistic model compared to PPP. In this paper, mmWave interfering base stations are considered to be GPP for deriving the coverage probability analysis. The proposed model considers the interfering base stations for analyzing the coverage probability. The closed form expression for the coverage probability is derived and is analyzed. The theoretical results are validated through simulation results.

Analysis and design procedure of a mm-Wave Class-E power amplifier

This paper presents a Class-E Power Amplifier (PA) design procedure for operation at mm-Wave frequencies, which accounts for the loss of passive components, ON-resistance (Ron) of the transistor, and its breakdown voltage (VBr). The quality factor of inductors is modeled with equivalent resistors and integrated into time-domain equations for the first time. The proposed procedure is examined for the design of a 24 ​GHz Class-E PA in 130 ​nm CMOS technology and compared with former best-known design recipes in the same technology node. Besides, a simplified design technique is introduced based on Ron-Cout (Cout is the transistor output capacitance) curves of the transistor versus its width, obtained by Harmonic Balance (HB) simulation. By the proposed method, the Figure of Merit (FoM) of the designed PA, including a combination of the output power, efficiency, and maximum drain voltage, is improved significantly (52%) compared to the other procedure outcomes in the literature.

A 44 To 64 GHz Broadband 90° Hybrid Doherty PA With Quasi Non-Foster Tuner in 0.13 μm SiGe

This letter presents a simultaneous broadband and back-off efficient mm-wave linear Doherty PA utilizing quadrature hybrid and a Doherty bandwidth enhancement technique exploiting quasi non-Foster impedance synthesis at the quadrature isolation port. We show analytically the design methodology of the non-Foster synthesis with ON-chip impedance tuner that allows broadband back-off efficiency, without suffering from nonlinearity due to the low-leakage power of the isolated port. Across 44-64 GHz, the proposed SiGe PA achieves collector efficiency of 26%-34.7% at peak power and 14%-23.2% at 6 dB back-off with 18.5-21.5 dBm Psat and peak gain of 18.5 dB. It supports 6 Gbps 64 QAM signal with -26.5 dB/-28.3 dBc EVM/ACLR at average Pout/PAE of 14.6 dBm/14.6% at 54 GHz. To the best of the authors' knowledge, this work achieves highest bandwidth among silicon-based mm-wave power amplifiers (PAs) where higher than class-B back-off efficiency is achieved.

Design optimization of the Upper Steering Mirror Assembly (USMA) for ITER ECHUL in view of disruptive events

Four Electron Cyclotron Heating Upper Launchers (ECHUL) will be used at ITER to counteract magneto-hydrodynamic plasma instabilities by targeting them with up to 20 MW of mm-wave power at 170 GHz. The millimeter waves are guided through a set of fixed mirrors (M1, M2 and M3) and the front steering mirror set (M4), aiming at the correct location in the plasma for suppression of the q = 3/2 and q = 2/1 Neoclassical Tearing Modes (NTMs). At the M4 reflecting mirror surfaces, part of the mm-wave power is converted into heat by ohmic dissipation, totaling ca. 25 kW of absorbed power and reaching a peak power density of up to 1.8 MW/m2 in each of the 4 beam center spots.The latest in-vessel mm-wave mirrors Components Load Specification (CLS) data imposes an increase of the electromagnetically induced loads relative to those anticipated in earlier designs, resulting in higher mechanical load on the Crossed Flexure Pivot (CFP) due to Vertical Displacements Events (VDEs). The present paper reports the main design optimizations as well as the finite elements analyses carried out with the objective to: 1) reduce the electromagnetic loads on the components due to induced Eddy currents, 2) dissipate the thermal loads coming from the beams themselves and the plasma following the design requirements in terms of coolant temperature rise, pressure drop and admissible corrosion rate values, 3) assure the components structural integrity enforcing the ITER Structural Design Code for the In-Vessel Components (SDC-IC).

The Most Popular Papers Published in 2019

Mobile and wireless communications are playing an irreplaceable role in our daily life. 5G is highly expected and can be considered as the convergence of mobile and wireless communications. This topic becomes one of the hottest research topics recently, and papers on this topic have been paid much attention. Table I lists the top ten papers published in the IEEE Transactions on Microwave Theory and Techniques (TMTT) in 2019 with the highest numbers of Full Text View since published. Seven papers are about millimeter-waves (mm-waves), and because mm-waves multiple-input–multiple-output (MIMO) will be adopted globally, the 24.25–27.5-GHz band and 27–29.5-GHz bands are now approved worldwide as the standard 5G communication bands. The most popular paper is published by Asbeck et al. [item 1) in the Appendix] for mm-wave power amplifiers.

Fluid-dynamic and thermo-mechanical analyses of the Monoblock Mitre Bend for the ITER electron cyclotron Upper launcher

The ITER Electron Cyclotron Heating (ECH) system will be used to counteract magneto-hydrodynamic plasma instabilities by aiming up to 20 MW of mm-wave power at 170 GHz. The primary vacuum boundary at the Electron Cyclotron Upper Launcher (EC UL) extends into the port cell region through eight beamlines, defining the so-called First Confinement System (FCS). Each beamline, designed for the transmission of 1.31 MW, is delimited by the closure plate at the port plug back-end and by a diamond window in the port cell. The FCS essentially consists of a Z-shaped set of straight corrugated waveguides (WG) connected by Mitre Bends (MB) with a nominal inner diameter of 50 mm. Due to the space restrictions, the eight MBs at the last FCS section are grouped into two monoblocks. Each Monoblock Mitre Bend (MBMB) consists of a body with corrugated feedthroughs defining a specific angle for each beamline and four mirrors attached by bolted connection to reflect the mm-wave power. The thermal expansion arising from the ohmic losses, the cooling pressure, the bolt pre-tension and the imposed displacements coming from the connection with the transmission lines are the primary design loads for the MBMBs. The fluid-dynamic analyses performed for both upper and lower MBMBs show that highest temperature takes place in the MB mirrors, reaching a maximum value of 203 °C at the beam center. The thermo-mechanical analyses demonstrate that the peak stress also occurs at this location with a maximum value of 324 MPa. These stresses are categorized and compared with the allowable limits defined in the ASME code, what probes that the current design of both upper and lower MBMBs are able to withstand the loads taking place during the mm-wave normal operation.

A 13.5-dBm 1-V Power Amplifier for W-Band Automotive Radar Applications in 28-nm FD-SOI CMOS Technology

This article presents a $W$ -band power amplifier (PA) for automotive radar applications. It was designed in a 28-nm fully depleted silicon-on-insulator CMOS technology with a transition frequency of around 270 GHz and a standard back-end-of-line. The circuit adopts a pseudo-differential topology with coupling transformers, which allow both compact matching networks and layout-optimized interstage interconnections. The power stage exploits a transformer-based folded-cascode structure that is very suitable for low-voltage mm-wave power applications. The PA is able to deliver a saturated output power as high as 13.5 dBm at 77 GHz with a power-added efficiency of 14.5%, while using a power supply as low as 1 V. The linear power gain is 26.5 dB and the current consumption is 150 mA. The PA occupies a core die size of $700\,\,\mu \text{m}\,\,\times 200\,\,\mu \text{m}$ .

A Highly Efficient and Linear mm-Wave CMOS Power Amplifier Using a Compact Symmetrical Parallel–Parallel Power Combiner With IMD3 Cancellation for 5G Applications

This paper presents a fully integrated linear power amplifier (PA) in a 65-nm CMOS process for mm-wave 5G applications. The proposed linear PA employs a compact symmetrical 4-way parallel–parallel power combiner with a third-order intermodulation distortion (IMD3) cancellation method to achieve high linear output power with a high power-added efficiency (PAE). An on-chip 4-way parallel–parallel power combiner, which combines the output power from 8-unit PAs, is designed with a compact footprint ( $241\,\,\mu \text{m}\,\,\times 241\,\,\mu \text{m}$ ). Conventional series power-combining transformer based power combiners have poor symmetrical performance for the amplitude and phase of the input impedance among unit PAs owing to the parasitic effects of the power combiners. However, the proposed parallel–parallel power combiner, which is based on parallel power-combining transformer structures, shows good symmetrical performances among unit PAs. Moreover, an IMD3 cancellation method using a parallel–parallel power combiner is proposed in this work. The proposed IMD3 cancellation method can support high-order modulation signals without increasing the complexity and reduce the dependence for digital predistortion (DPD). Consequently, the proposed linearization method obtains a high linear POUT and PAE without DPD. The PA in 65-nm CMOS demonstrates a saturated output power (PSAT) of 23.2 dBm, a 15.9-dB power gain, a 1-dB compressed output power ( $\text{P}_{\mathrm {O,1dB}}$ ) of 22 dBm, and a peak power-added efficiency (PAE) of 33.5% at 28 GHz. The measured error vector magnitude with 100 Msym/s of 256/512-QAM is −31.2/−32.1 dB with average output power of 18.02/17.73 dBm, average PAE of 17.6/16.1%, and adjacent channel power ratio (ACPR) of −30/−33.1 dBc without DPD. To the best of the authors’ knowledge, the proposed PA demonstrates high output power with the highest PAE performance supporting 256/512-QAM compared to the recently published fully integrated mm-wave 5G CMOS PAs.

Millimeter-Wave Power Amplifier Integrated Circuits for High Dynamic Range Signals

The next-generation 5G and beyond-5G wireless systems have stimulated a substantial growth in research, development, and deployment of mm-Wave electronic systems and antenna arrays at various scales. It is also envisioned that large dynamic range modulation signals with high spectral efficiency will be ubiquitously employed in future communication and sensing systems. As the interface between the antennas and transceiver electronics, power amplifiers (PAs) typically govern the output power, energy efficiency, and reliability of the entire wireless systems. However, the wide use of high dynamic range signals at mm-Wave carrier frequencies substantially complicates the design of PAs and demands an ultimate balance of energy efficiency and linearity as well as other PA performances. In this review paper, we will first introduce the system-level requirements and design challenges on mm-Waves PAs due to high dynamic range signals. We will review advanced active load modulation architectures for mm-Wave PAs and power devices. We will then introduce recent advances in mm-Wave PA technologies and innovations with several design examples. Special design considerations on mm-Wave PAs for phased array MIMOs and high mm-Wave frequencies will be outlined. We will also share our vision on future technology trends and innovation opportunities.

Microwave and Millimeter Wave Power Beaming

Power beaming is the efficient point-to-point transfer of electrical energy across free space by a directive electromagnetic beam. This paper clarifies the basic principles of power beaming in simple terms, and proposes a benchmarking methodology for improving the comparative assessment of power beaming systems and technology. An in-depth historical overview tracing the worldwide progress in microwave and millimeter wave (mmWave) experimental demonstrations over the past 60 years shows clear evidence of a significant increase in activity during the last 5 years. In addition, a review of progress in scalable rectenna arrays for the reception of microwave power beaming shows sufficient maturity for new research to initiate on the ruggedization, productization, and system integration aspects of the technology. A review of regulatory issues including spectrum management and safety indicates the need for additional technical solutions and international coordination. Breaking results reported in this paper include 1) data from the first in-orbit flight test of a solar-to-RF “sandwich module”, 2) the construction of multiple US in-orbit demonstrations, planned for 2023 launch, that will demonstrate key technologies for space-based solar power, and 3) a 100-kW mmWave power beaming transmitter demonstrating inherent human life safety.

Towards high-power, high-coherence, integrated photonic mmWave platform with microcavity solitons

Millimetre-wave (mmWave) technology continues to draw great interest due to its broad applications in wireless communications, radar, and spectroscopy. Compared to pure electronic solutions, photonic-based mmWave generation provides wide bandwidth, low power dissipation, and remoting through low-loss fibres. However, at high frequencies, two major challenges exist for the photonic system: the power roll-off of the photodiode, and the large signal linewidth derived directly from the lasers. Here, we demonstrate a new photonic mmWave platform combining integrated microresonator solitons and high-speed photodiodes to address the challenges in both power and coherence. The solitons, being inherently mode-locked, are measured to provide 5.8 dB additional gain through constructive interference among mmWave beatnotes, and the absolute mmWave power approaches the theoretical limit of conventional heterodyne detection at 100 GHz. In our free-running system, the soliton is capable of reducing the mmWave linewidth by two orders of magnitude from that of the pump laser. Our work leverages microresonator solitons and high-speed modified uni-traveling carrier photodiodes to provide a viable path to chip-scale, high-power, low-noise, high-frequency sources for mmWave applications.

Characterization of photonic band resonators for DNP NMR of thin film samples at 7 T magnetic field

Polarization of nuclear spins via Dynamic Nuclear Polarization (DNP) relies on generating sufficiently high mm-wave B1e fields over the sample, which could be achieved by developing suitable resonance structures. Recently, we have introduced one-dimensional photonic band gap (1D PBG) resonators for DNP and reported on prototype devices operating at ca. 200 GHz electron resonance frequency. Here we systematically compare the performance of five (5) PBG resonators constructed from various alternating dielectric layers by monitoring the DNP effect on natural-abundance 13C spins in synthetic diamond microparticles embedded into a commercial polyester-based lapping film of just 3 mil (76 μm) thickness. An odd-numbered configuration of dielectric layers for 1D PBG resonator was introduced to achieve further B1e enhancements. Among the PBG configurations tested, combinations of high-ε perovskite LiTaO3 together with AlN as well as AlN with optical quartz wafers have resulted in ca. 40 to over 50- fold gains in the average mm-wave power over the sample vs. the mirror-only configuration. The results are rationalized in terms of the electromagnetic energy distribution inside the resonators obtained analytically and from COMSOL simulations. It was found that average of B1e2 over the sample strongly depends on the arrangement of the dielectric layers that are the closest to the sample, which favors odd-numbered PBG resonator configurations for their use in DNP.

First RF Power Operation of AlN/GaN/AlN HEMTs With &gt;3 A/mm and 3 W/mm at 10 GHz

The AlN/GaN/AlN heterostructure is attractive for microwave and millimeter-wave power devices due to its thin top barrier, tight carrier confinement, and improved breakdown voltage. This work explores the large-signal RF performance of high-electron-mobility transistors on this heterostructure. Results are highlighted by record high on-current of 3.6 A/mm, and record maximum oscillation frequency ( $f_{max}$ ) of 233 GHz. The load-pull power sweep at 10 GHz demonstrate a peak power added efficiency (PAE) of 22.7% with an associated gain ( $G_{T}$ ) of 8.7 dB and output power ( $P_{out}$ ) of 3 W/mm. When optimized for power, the peak $P_{out}$ of 3.3 W/mm has an associated PAE of 14.7% and $G_{T}$ of 3.2 dB. This first demonstration is encouraging for the mm-wave power potential of the AlN/GaN/AlN HEMT.

Realization of a Compact and High-Performance Power Divider Using Parallel RC Isolation Network

In this brief, the design methodology of high- performance lumped-distributed Wilkinson power divider with extremely small chip area is proposed. A parallel capacitor is included at the input port (port 1) to compensate the imaginary part of the input admittance for input matching. A parallel RC network is connected between the output ports (ports 2 and 3) to attain perfect input matching and isolation of the output ports in the odd- and the even-mode excitations. Dual spiral structure with transmission line length of about λ/10 and symmetrical layout is adopted to achieve miniature area and small amplitude imbalance (AI) and phase difference (PD). At 33 GHz, the prototyped power divider achieves S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> of -17.8 dB, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> and S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> of -22.7 dB, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">32</sub> of -34.7 dB, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> of -4.1 dB, and S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sub> of -4.07 dB. The corresponding AI is -0.03 dB and PD is -0.08°. The chip area is only 1.2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , one of the smallest normalized chip area ever reported for millimeter-wave (mm-wave) power dividers. The superb results of the power divider indicate that it is suitable for power division/combination in mm-wave transceivers.

Electromagnetic and mechanical analyses of the ITER electron cyclotron Upper launcher steering M4 mirrors for the vertical displacement event

Abstract The mm-wave power exiting the eight In-Vessel waveguides inside the ITER Electron Cyclotron Upper Launcher is reflected by three fixed mirror sets and finally aimed by two independent steering mirrors to specific plasma locations. A design solution for both Upper and Lower Steering M4 Mirrors capable to withstand the loads taking place during normal operation was already proposed. This design is now assessed against the Vertical Displacement Event Category III (VDEIII) linear decay (36 ms) scenario, which was identified as one of the most stringent load combinations for the steering M4 mirrors. This paper reports the analyses performed to quantify the mechanical loads induced in the steering M4 mirrors during the VDEIII scenario as well as the structural integrity assessment to validate the design against these loads. The transient electromagnetic simulations show that the highest forces are induced in the reflecting surfaces, which produce a bending moment that tends to rotate upwards the mirrors. The comparison between the categorized stresses obtained from the transient mechanical analyses and the allowable design limits according to the ASME code shows that the design of the steering M4 mirrors is widely capable of withstanding the expected loads taking place during the VDEIII scenario.