Broadband GaN HEMT push-pull microwave power amplifier

We report a broadband, linear, push-pull amplifier that utilizes GaN-based HEMTs grown on SiC substrates. The high power density capabilities of these devices can be enhanced by the high efficiency achievable with push-pull operation. Good amplifier performance is facilitated by use of a new low-loss balun that is implemented with three symmetric coupled lines and which showed insertion loss of less than 0.5 dB per balun. The bias was injected through the baluns, thereby simplifying the amplifier design and reducing loss associated with dc decoupling capacitors. Using two 1.5 mm HEMTs with 0.35-μm gate length, a push-pull amplifier produced a small-signal gain of 8 dB at 5 GH2, a 3 dB bandwidth of 3.5-10.5 GHz, and a PAE of 25%     

A class-B push-pull power amplifier based on an extended resonance technique

A class B push-pull power amplifier based on an extended resonance power combining technique is presented. In this design, advantages of push-pull power amplifier, such as doubling power capability and reduced common lead effects, have been achieved with a simple and compact circuit topology. The measured power combining efficiency (PCE) is 93% with 1-dB bandwidth of 12.6% at 1.75 GHz. The measured output power at 1-dB compression is 30 dBm with power added efficiency (PAE) of 59%.     

Theory of a new three-terminal microwave power amplifier

The feasibility of a new three-terminal linear power amplifier has been demonstrated both theoretically and experimentally from 0.5 to 3.0 GHz. The new amplifier is similar to an n-p-n bipolar transistor in configuration but develops extra power gain through avalanche multiplication and by the use of transit time in the collector. Major differences in the construction of the two devices are in their collector doping profiles and depletion layer widths. It is estimated that this new amplifier will be capable of several watts of power output at 10 GHz with useful gain, good linearity, and wide dynamic range. An acronym, CATT, which stands for controlled avalanche transit-time triode, is used to designate this new microwave semiconductor device. In this paper, the theory of the CATT is developed. It is found to be dc and RF stable. The necessary conditions on the ionization coefficients for signal amplification are investigated. The emitter-base dynamics of the CATT are shown to be quite different from a transistor due to hole feedback from the avalanche multiplication region. This phenomena results in a more uniform emitter current injection and better use of the emitter finger area than for transistors.     

Characterization of a low-noise linearized microwave power amplifier module

An X-band, low-noise, linearized microwave power amplifier module consisting of a low-noise solid-state amplifier (SSA), predistortion linearizing circuit, and low-gain helix traveling wave tube (TWT) is designed and tested in order to demonstrate both reduced noise figure and suppressed intermodulation distortion ratio. Two-tone intermodulation distortion (IMD) ratios are predicted from simulations obtained from modeling of the TWT, linearizing circuit, and SSA by the use of Agilent's Advanced Design System simulation code. Simulated IMD ratios are in good agreement with measured results. Measurements show a noise figure of 2.2 dB at 9.5 GHz and the third-order IMD ratio of -53 dBc at 10 dB input back off from the input P1dB point. It is found that both noise figure and IMD ratio are significantly improved compared with conventional helix-TWTs and microwave power modules.     

ESD sensitivity of a GaAs MMIC microwave power amplifier

The EOS/ESD sensitivity of the main circuit blocks of a complete GaAs multi-stage power amplifier for microwave applications was investigated under HBM, MM and TLP regimes. Hard breakdown failure modes were identified due to passive components failure. The high current injection state of active components was also analyzed.     

Low-harmonic distortion in single-ended and push-pull class E power amplifier by using slotted microstrip lines

In this work, a very low-harmonic distortion with high power-added efficiency (PAE) power amplifier (PA) with slotted microstrip lines is reported. The circuit is a push-pull class E amplifier, terminated with defected structures to improve the spectrum purity and efficiency. The relationship of the second and third harmonic to the fundamental is 70 and 54 dBc, respectively. The amplifier is developed with HBT medium power transistors. The circuit works at 1.8 GHz obtaining a PAE close to 60%, delivering an output power of 24 dBm with a power gain of 13.3 dB.     

Integrated-antenna push-pull power amplifiers

In this paper, the integrated-antenna concept is applied to push-pull power amplifiers (PAs). In this approach, the antenna serves as an out-of-phase power combiner and tuned load for higher harmonics. This new architecture effectively has a near-zero loss output hybrid, and results in a high-efficiency PA. The first example is a narrow-band push-pull amplifier integrated with a dual-feed patch antenna. At an operating frequency of 2.5 GHz, a maximum measured power-added efficiency (PAE) of 55% is achieved. The second example is a broadband push-pull amplifier integrated with a dual-feed slot antenna amplifier operating at 2.46 GHz which has a peak PAE of 63%, and PAE better than 55% in an 8% bandwidth. Additionally, 48% PAE is achieved with code-division multiple-access modulation and adjacent-channel power ratio better than -42 dBe at a 1.25-MHz offset     

0.18-/spl mu/m CMOS push-pull power amplifier with antenna in IC package

A novel architecture of power amplifier with antenna implemented in a ceramic ball grid array (CBGA) package is presented. The monolithic power amplifier designed in a standard 0.18- /spl mu/m CMOS technology offers 19.5 dBm maximum output power at 5.2 GHz to the antenna with the PAE of 32%. The antenna integrated in the CBGA package achieves impedance bandwidth of 3.86% and gain of 2 dBi at 5.2 GHz. Results demonstrate the feasibility of using this innovative configuration to the design of single-chip 5 GHz transmitter front-end.     

基于ADS高效率微波功率放大器设计

基于ADS软件,选取合适的静态直流工作点,采用负载牵引法得到LDMOS晶体管BLF7G22L130的输出和输入阻抗特性,并通过设计和优化得到最佳的共轭匹配网络,设计出高效率功率放大器。ADS设计仿真表明该功率放大器在中心频率2 160 MHz处的效率达到70%,稳定性好、增益平坦度小等优点。     

A high-performance CMOS power amplifier

A high-performance CMOS power amplifier consisting of a new input stager especially suited to power amplifier applications and a variation on a class AB output stage is presented. The amplifier has been fabricated using a conventional silicon gate p-well process. The configuration results in several performance improvements over previously reported high-output current amplifiers without requiring process enhancements. Design details and experimental results are described.     

A potentially low-noise avalanche diode microwave amplifier

A sequence of AlGaAs, GaAs heterojunctions can be used to generate a series of potential steps that are just large enough to accelerate conduction-band electrons to energies above the impact-ionization threshold while valence-band holes do not obtain this much energy. The smaller difference in the valence-band heterojunction discontinuity and the higher scattering rate for holes than conduction-band electrons are shown to suppress the initiation of impact ionization by valence-band holes in this structure. The resulting transit-time device is predicted to be a relatively low-noise amplifier or oscillator that can be used in the microwave region and will be insensitive to small fluctuations in the power supply voltage.     

8 GHz, 10 W solid-state power amplifier for microwave digital radio

An 8 GHz, 10 W GaAs FET prototype power amplifier has been developed to replace the TWT in the Northern Telecom's digital microwave radio system. For a single bit stream of 91.04 Mbit/s, the residual bit error rate at 40 dBm output level was 1.0×10?32 compared with 1.0×10?23 for TWT; the AM/AM conversion ratio was 0.375 dB/dB and AM/PM was 0.84°/dB. The total mean time between failure of the amplifier was 350 000 h.     

High-dynamic-range low-noise microwave amplifier

The operation of a high-dynamic-range parametric amplifier is described. The varactor is a GaAs p?n junction with an n type layer suitable for operation as a K band transferred-electron oscillator (t.e.o.). A dynamic range of approximately 177 dB/Hz and a noise figure of less than 2 dB were measured at C band. The tests were made to show the feasibility of high-dynamic-range low-noise microwave amplification for radar-receiver applications, and to establish the feasibility of high-performance monolithic multifunction chips from the material standpoint.     

A microwave gyro amplifier with a ferroelectric cathode

A ferroelectric cathode is employed for the first time as the electron-beam source in a microwave amplifier tube. A PLZT 12/65/35 ferroelectric ceramic with a high dielectric constant (ϵ_r ~4000) is used in a form of a hollow cathode. The tube is operated in poor vacuum conditions (2×10^-5 Torr) at room temperature, in a mechanism of a cyclotron-resonance maser amplifier. The device operates near the waveguide cutoff frequency at 6927 MHz. A 22-dB electronic gain and a 25-W output power are measured in this experiment     

Novel W-band monolithic push-pull power amplifiers

Monolithic W-band push-pull power amplifiers have been developed using 0.1-μm AlGaAs/InGaAs/GaAs pseudomorphic T-gate power HEMT technology. The novel design approach utilizes a push-pull topology to take advantage of a virtual ground between the device pair, eliminating the series feedback of the via hole inductance, and thus improving the performance of the power amplifier at millimeter-wave frequencies. For a two-stage design presented in this paper, the measurement results show a small signal gain of 13 dB and a saturated output power of 19.4 dBm at 90 GHz. The best power added efficiency of 13.3% has been achieved at an output power of 18.8 dBm under a lower bias condition. The gain and efficiency results represent state-of-the-art performance. These are the first reported monolithic push-pull amplifiers at millimeter-wave frequencies     

Analysis of a microwave power amplifier using a combiner/dividerwith circular cavities

Equations based on the discrete Fourier transformation developed for the analysis of a microwave power amplifier consisting of unit amplifiers and a power combiner/divider with circular cavities are presented. Equations of the mode voltages and currents of a power amplifier with some failed unit amplifiers are provided. The equations are obtained by taking into account the spurious-mode excitation to the cavity from the unit amplifiers, and are developed by using an analogous expansion by the discrete Fourier transformation (DFT). Equivalent circuits of the power amplifier for the various mode excitations are discussed, and load admittances for the spurious-mode excitations are applied to the equations for calculating the gain of the amplifier. The load admittance is analytically obtained using variational methods for a combiner with coaxial input/output ports. Numerical results for the power amplifier gain when there is a failed unit amplifier are shown. The effects of gain of the capability of suppressing spurious-mode waves using slits in the combiner are clarified     

Gallium-nitride microwave Doherty power amplifier with 40 W PEP and 68% PAE

A 40 W gallium-nitride microwave Doherty power amplifier for WCDMA repeater applications is presented. The main amplifier and peaking amplifier are implemented using two 20 W PEP GaN HEMTs. Performance is evaluated for broadband gain, power efficiency and adjacent-channel-power-ratio (ACPR). Experimental results of the GaN Doherty amplifier yielded a power gain of over 11 dB from 1.8 to 2.5 GHz, 68% power added efficiency at 40 W peak power. Good linearity performance of -48 dBc ACPR is obtained at a peak-to-average ratio of 9.8 dB.     

基于FLM3135-18F的S波段微波功率放大器设计

介绍了基于阻抗内匹配GaAs FET微波场效应管FLM3135-18F全固态线性高功率放大器的设计,介绍了功率放大器系统原理以及FLM3135-18F.