Measured Peak Output Power Research Articles

Comparative demonstration of multimode steady-state theory for the gyrotron traveling-wave tube based on a distributed loss-loaded metal cylindrical waveguide

Gyrotron traveling-wave tube (gyro-TWT) is capable of generating high-power microwave radiation in a millimeter wave range. It is one of the most promising candidates for the applications in the millimeter wave radar, communication systems, and environmental monitoring. The gyro-TWT can work at high frequency and produce high power output with high order modes. Although the high mode gyro-TWT can work at high frequency and produce high power output, the instability problem is a main factor to prevent the gyro-TWT performance from further improving and hinder this device from being put into the practical application. The earlier research of the instability primarily concentrated on the single-mode situation, which cannot be used to analyze the mutual effects between the other oscillation modes and the operating mode. Hence, it is important for academic study and engineering application to solve the mode competition problem. In this paper, based on lossy uniform/periodic dielectric-loaded metal cylindrical waveguide usually used in the international academic analysis and engineering research, a multimode steady-state beam wave interaction theory for gyro-TWT is established, which can consider the mutual effects between the other oscillation modes and the operating mode. As application examples, under the same condition of geometrical and electrical parameters, the theoretical results of the beam wave interaction for the TE01 fundamental mode gyro-TWTs are compared with the experimental results reported by NRL and IECAS for Ka band and those simulated with Magic code for W band in order to demonstrate the rationality of the theory. The results show that the theoretical results are in good agreement with the experimental and simulated ones. For the NRL design, when the velocity spread is 9.6%, the maximum output power from the theory is 127 kW at 34.09 GHz with a gain of 47.4 dB, an efficiency of 17.6%, and a -3 dB bandwidth of 1.01 GHz, and an NRL measured maximum output power is 130 kW at 34 GHz with a gain of 47.5 dB, an efficiency of 18% and a -3 dB bandwidth of 1.0 GHz. The maximum difference between the theory and the experiments occurs near the frequency of 34 GHz, the measured power by NRL is 127 kW and the calculated power is 118 kW, the relative error between the theory and the experiment is 8.5%. For the IECAS design, the simulated maximum output power from the theory is 113.73 kW at 33.85 GHz with a -3 dB bandwidth of 1.72 GHz when the velocity spread is 7%. The measured peak output power by IECAS is 110 kW at 33.88 GHz with a -3 dB bandwidth of 1.75 GHz. For a W band TE01 fundamental mode gyro-TWT design, the saturated output power is 112 kW at a frequency of 94.5 GHz with a gain of 34.28 dB and -3 dB bandwidth of about 4.1 GHz, and the saturated output power calculated with Magic code is 106.7 kW with a gain of 34.11 dB and 3 dB bandwidth of 3.9 GHz, the maximum relative errors between the theory and experiment are both about 5% for the output power and the bandwidth.

A Wideband SiGe BiCMOS Frequency Doubler With 6.5-dBm Peak Output Power for Millimeter-Wave Signal Sources

This paper presents a balanced frequency doubler with 6.5-dBm peak output power at 204 GHz in 130-nm SiGe BiCMOS technology ( f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> = 210/250 GHz). To convert the single-ended input signal to a differential signal for balanced operation, an on-chip transformer-based balun is employed. Detailed design procedure and compensation techniques to lower the imbalance at the output ports, based on mixed mode S parameters are proposed and verified analytically and through electromagnetic simulations. The use of optimized harmonic reflectors at the input port results in a 2-dBm increase in output power without sacrificing the bandwidth of interest. The measured conversion loss of the frequency doubler is 9 dB with 6-dBm input power at 204-GHz output. The measured peak output power is 6.5 dBm with an on-chip power amplifier stage. The 3-dB output power bandwidth is measured to be wider than 50 GHz (170-220 GHz). The total chip area of the doubler is 0.09 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and the dc power consumption is 90 mW from a 1.8-V supply, which corresponds to a 5% collector efficiency.

645‐GHz InP heterojunction bipolar transistor harmonic oscillator

645-GHz signal generation with a harmonic oscillator based on a 250-nm InP heterojunction bipolar transistor technology is demonstrated. The oscillator is based on the common-base cross-coupled topology, generating a second harmonic signal through the push–push operation. The fabricated oscillator exhibits oscillation frequencies ranging from 561.5 to 645.1 GHz with bias variation. The measured peak output power is –17.4 dBm with a dc power dissipation of 49.3 mW (dc-to-RF efficiency of 0.04%). Additionally, terahertz imaging was successfully demonstrated with the developed oscillator employed as a signal source.

A Q-band low noise GaAs pHEMT MMIC power amplifier for pulse electron spin resonance spectrometer.

We present the design and development of a single stage pulse power amplifier working in the frequency range 32-38 GHz based on a monolithic microwave integrated circuit (MMIC). We have designed the MMIC power amplifier by using the commercially available packaged GaAs pseudomorphic high electron mobility transistor. The circuit fabrication and assembly process includes the elaboration of the matching networks for the MMIC power amplifier and their assembling as well as the topology outline and fabrication of the printed circuit board of the waveguide-microstrip line transitions. At room ambient temperature, the measured peak output power from the prototype amplifier is 35.5 dBm for 16.6 dBm input driving power, corresponding to 19 dB gain. The measured rise/fall time of the output microwave signal modulated by a high-speed PIN diode was obtained as 5-6 ns at 20-250 ns pulse width with 100 kHz pulse repetition rate frequency.

A 70-GHz LO Phase-Shifting Bidirectional Frontend Using Linear Coupled Oscillators

A 70-GHz two-element bidirectional frontend is demonstrated with linear coupled oscillators in a 90-nm silicon–germanium BiCMOS process. The transmitter has a measured peak output power of 7.2 dBm and a peak conversion gain of 14.5 dB while consuming 47 mA from a 1.8-V supply. The receiver has a peak conversion gain of 9.9 dB and a minimum noise figure of 8.6 dB with a nominal current consumption of 18 mA from a 1.5-V supply. The frontend is integrated with a two-element linear coupled oscillator array and achieves a maximum phase scanning of ±80°.

A 10 dBm Output Power D-Band Power Source With 5 dB Conversion Gain in BiCMOS 55nm

A D-Band power source implemented in the STMicroelectronics BiCMOS 55 nm technology and dedicated to on wafer characterization in millimeter-wave band frequency is presented. The circuit consists in multiplying by four a low frequency signal by cascading two frequency doublers. Two intermediate power amplifiers optimized at the second and fourth harmonics respectively are implemented after each doubler. A high-pass filter implemented before the second amplifier performs the rejection of the first and second harmonics to obtain a pure fourth harmonic output frequency. The measured peak output power is 10 dBm at 140 GHz with a −3 dB bandwidth of 24 GHz and a DC power consumption of 0.61 W. The total chip area is $1.7 \times 1.35$ mm2.

Dominance of radiative recombination from electron-beam-pumped deep-UV AlGaN multi-quantum-well heterostructures

AlGaN-based multiple-quantum-well (MQW) heterostructures were irradiated with a pulsed electron beam. Excitation with a beam energy of 12 keV and a beam current of 4.4 mA produced cathodoluminescense at λ=246 nm with a measured peak output power of &amp;gt;200 mW. The emission is dominated by radiative recombination from the MQW up to the maximum tested excitation power density of 1 MW/cm2, as evidenced by unity slope in a double-logarithmic plot of the light output power vs. excitation power density. Monte Carlo simulations of the depth distribution of deposited energy for different beam energies produced good agreement with the measured peak output power vs. beam energy for an assumed carrier diffusion length of ∼200 nm.

Supply-Scaling for Efficiency Enhancement in Distributed Power Amplifiers

Distributed amplifiers (DAs) feature large bandwidth but relatively low gain and power efficiency. This paper presents a supply-scaling technique to improve the efficiency of a mm-wave DA while maintaining a broadband $50\Omega $ match. An analysis of interstage load modulation and the effects of shunt dc-feed inductors on distributed operation is provided. A single-ended, eight-stage DA is designed in a 90 nm SiGe BiCMOS process. The fabricated amplifier has a gain of 12 dB over a 3 dB bandwidth from 14-105 GHz. The measured peak output power is 17 dBm with a peak power-added efficiency (PAE) of 12.6% at 50 GHz and 3 dB power bandwidth greater than 70 GHz. The DA occupies an area of 2.65 mm × 0.57 mm, and total dc power consumed from four scaling voltage supplies is 297 mW.

A Digitally Intensive Transmitter/PA Using RF-PWM With Carrier Switching in 130 nm CMOS

A digitally intensive transmitter using RF pulse-width-modulation (PWM) with a class-D power amplifier (PA) is described. The use of carrier switching for alleviating the dynamic range limitation that can be observed in classical RF-PWM implementations is introduced. The approach employs full carrier frequency for half of the amplitude range and the second harmonic of half of the carrier frequency, for the remainder of the amplitude range. This concept not only allows the transmitter to drive modulated signals with large peak-to-average power ratios (PAPR) but also improves back-off efficiency due to reduced switching losses in the half carrier-frequency mode. A glitch-free phase selector is proposed that removes the deleterious glitches that can occur at the input data transitions. The phase-selector also prevents D flip-flop setup-and-hold time violations. The transmitter has been implemented in a 130-nm CMOS process. The measured peak output power and power-added-efficiency (PAE) are 25.6 dBm and 34%, respectively. While driving 802.11g 20 MHz 64-QAM OFDM signals, the average output power is 18.3 dBm and the PAE is 16% with an EVM of $-25.5\; \text{dB}$ .

High temperature operation of far infrared (λ ≈20 µm) InAs/AlSb quantum cascade lasers with dielectric waveguide.

We demonstrate the high temperature operation, up to 80°C, of quantum cascade lasers emitting at a wavelength of 20 µm. The lasers are based on the InAs/AlSb materials and take benefit of a low loss plasmon-enhanced dielectric waveguide. The waveguide consists of doped InAs cladding layers and low-doped InAs spacers. For 2.9-mm-long devices, the threshold current density is 4.3 kA/cm2 and the measured peak output power is 7 mW at room temperature. The cavity length dependence of the threshold currents also indicates that very large optical gain is achieved and effectively overcome the strong free carrier absorption.

A 0.54 THz Signal Generator in 40 nm Bulk CMOS With 22 GHz Tuning Range and Integrated Planar Antenna

This work presents the design and measurements of a 0.54 THz signal generator implemented in a 40 nm bulk CMOS technology. An LC-VCO operating at 180 GHz is connected to a nonlinear buffer, which is designed to generate the wanted third harmonic at 540 GHz. The third harmonic is coupled via a transformer to the output. The developed techniques are implemented on two different chips: one with a probe pad for on-wafer measurements and one with an on-chip planar dipole. The measured peak output power using a WR-1.5 probe is -31 dBm at 543 GHz, for 16.8 mW of dc power consumption. By changing value of the parasitic I-MOS varactors of the LC-VCO (“parasitic tuning”), the output frequency can be tuned from 561.5 to 539.6 GHz, resulting in a 21.9 GHz tuning range, which is the highest reported so far for CMOS THz oscillators. The 3-dB output bandwidth is 5.5 GHz. The 540 GHz signal generator with on-chip antenna is used for THz imaging without the use of substrate or focusing lenses, demonstrating some of the capabilities of CMOS for low-cost, mass-produced THz imagers.

A Class-G Switched-Capacitor RF Power Amplifier

A switched-capacitor power amplifier (SCPA) that realizes an envelope elimination and restoration/polar class-G topology is introduced. A novel voltage-tolerant switch enables the use of two power supply voltages which increases efficiency and output power simultaneously. Envelope digital-to-analog conversion in the polar transmitter is achieved using an SC RF DAC that exhibits high efficiency at typical output power backoff levels. In addition, high linearity is achieved and no digital predistortion is required. Implemented in 65 nm CMOS, the measured peak output power and power-added efficiency (PAE) are 24.3 dBm and 43.5%, respectively, whereas when amplifying 802.11g 64-QAM OFDM signals, the average output power and PAE are 16.8 dBm and 33%, respectively. The measured EVM is 2.9%.

A $+$31.5 dBm CMOS RF Doherty Power Amplifier for Wireless Communications

A fully differential Doherty power amplifier (PA) is implemented in a 0.13-mum CMOS technology. The prototype achieves a maximum output power of +31.5 dBm with a peak power-added efficiency (PAE) of 36% (39% drain efficiency) with a GMSK modulated signal. The PAE is kept above 18% over a 10 dB range of output power. With a GSM/EDGE input signal, the measured peak output power while still meeting the GSM/EDGE mask and error vector magnitude (EVM) requirements is +25dBm with a peak PAE of 13% (PAE is 6% at 12 dB back-off). Instead of using a bulky lambda/4 transmission line, a passive impedance inverter is implemented as a compact lumped-element network. All circuit components are fully integrated on a single CMOS die except for an off-chip capacitor for output matching and baluns. The die size is 2.8times3.2mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> including all pads and bypass capacitors

A&amp;lt;tex&amp;gt;$rm TE_11$&amp;lt;/tex&amp;gt;&amp;lt;tex&amp;gt;$K_a$&amp;lt;/tex&amp;gt;-Band Gyro-TWT Amplifier With High-Average Power Compatible Distributed Loss

Current amplifier research at the Naval Research Laboratory Vacuum Electronics Branch emphasizes techniques to extend the bandwidth and average power capability of gyro devices for millimeter wave radar applications. This paper will discuss the implementation of a wideband high-gain gyro-traveling wave tube amplifier design, with a measured peak output power of 78 kW, gain /spl sim/60 dB, and a 3-dB bandwidth of 4.2 GHz (12%) at 52 kW in K/sub a/-band. The 3-dB saturated bandwidth at 70 kW is 6 GHz (17%), which is also the instantaneous bandwidth with appropriately tailored input power (e.g., gain equalizer). The amplifier operates in the TE/sub 11/ mode and for stabilization employs a high-average power compatible diffractive loading technique.