Push-pull Power Amplifier Research Articles

Digital Predistortion Linearization of a GaN HEMT Push-Pull Power Amplifier for Cable Applications With High Fractional Bandwidth

This paper presents two linearization strategies for a custom-designed wideband push-pull (PP) power amplifier (PA) for wired communication applications such as, for example, cable TV. Two digital predistortion (DPD) behavioral models are proposed to meet the in-band and out-of-band linearity requirements when efficiently amplifying wideband DOCSIS signals with high fractional bandwidth (FBW). A radiofrequency (RF) DPD linearizer based on a band-pass generalized memory polynomial (BP-GMP) behavioral model and a baseband (BB) I-Q DPD linearizer based on a harmonic distortion GMP (HD-GMP) behavioral model are proposed. Both DPD models take into account the harmonic distortion typical of high FBW amplification. Experimental results will show high efficient and linear amplification of a 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 192 MHz composite DOCSIS signal by properly combining a crest factor reduction (CFR) technique and the proposed DPD strategies.

Computer simulation of a push-pull power amplifier

The paper presents the results of computer simulation of power amplifiers based on bipolar and complementary Darlington transistors. It is shown that the constant voltage gain is ensured by changing the current gain in the range from 103 to 105.

A lumped‐element balun design with multi‐interference suppression for push–pull power amplifier

SummaryIn this article, a lumped‐element balun with multi‐interference suppression is implemented and presented. Originated from the conventional lattice LC balun, the balun combining two Π‐networks is expended to four new topologies. By constructing frequency traps and out‐of‐phase combining pathways, the new topologies can realize two‐ or three‐interference suppression while maintaining well‐matched input/output impedances. The concept is studied theoretically in both even and odd mode circuits, and analytical design equations are also derived. Based on the design theory, four interference suppression balun topologies are proposed for push–pull power amplifiers. To verify the design concept, two of the four topologies working at 1 GHz are prototyped and measured. The measured results agree well with the analysis and simulation results. The two baluns both achieve good performance with low insertion loss better than −3.9 dB, low return loss less than −13.6 dB, good interference suppression more than 24.7 dB, and small phase unbalance less than 0.8°. Furthermore, the proposed balun is used in a gallium nitride push–pull power amplifier to validate the 2nd and 3rd harmonic suppression. The amplifier works at 1 GHz with a typical gain of 16.7 dB. At least −45 dBc interference suppression, 52.6% power‐added efficiency, and 34.6 dBm P1dB output power are obtained.

Low-Power Low-Complexity FM-UWB Hybrid Transceiver for Communication and Ranging

A frequency-modulated ultrawideband (FM-UWB) hybrid transceiver, with a high system reuse ratio up to 90%, is fabricated in the 65-nm CMOS process for both short-range wireless communication and high-resolution radar ranging. The radio frequency (RF) front-ends (RFFEs) based on module stacking and current reuse achieve significant RF power savings of about 30% and 50% for the transmitter and the receiver (RX), respectively. The presented IF zero-crossing delay discrimination benefits a high radar resolution less than 1 cm. A multimode relaxation oscillator (OSC) for the reconfigured triangular subcarrier generation and a dual-path ring voltage-controlled oscillator (VCO) for the linear FM, stacked by a wideband push–pull power amplifier (PA), generate an FCC-compliant UWB signal. An active balun embedded low-noise amplifier (LNA) and two symmetric-detuning band-passed filters (BPFs) are stacked with the bandwidth extension to linearly demodulate the UWB FM signal. Experimental results show that the 3.75–4.25-GHz hybrid transceiver has an energy efficiency of 1.9 nJ/bit with an active area of 0.7 mm2 and a power dissipation of 1.9 mW and achieves the RX sensitivity of −71 dBm and the transmitted power of −14.1 dBm, with a bit error rate (BER) of 10−4 at a distance of 4 m under the data rate (DR) of 0.1–1.0 Mbps. The transceiver also achieves the noise figure (NF) of 4.8 dB and the phase noise of −78.6 dBc/Hz at 1-MHz offset frequency.

A 1.15-mW Low-Power Low-Complexity Reconfigurable FM-UWB Transmitter

A 1.15-mW 3.75–4.25-GHz frequency-modulated ultrawideband (FM-UWB) transmitter (TX) is fabricated in 65-nm CMOS, with digitally reconfigurable subcarrier frequencies, UWB bandwidth, and radio frequency (RF) frequency band. Low-complexity submodules are utilized with significant power savings. An ultralow-current hybrid module is for bandgap reference (BGR) and power-ON reset (POR), and a single-ended crystal oscillator (XO) generates a 12-MHz clock reference. A dual-path ring voltage-controlled oscillator (VCO) conducts linear RF FM, followed by a push–pull power amplifier (PA) for 100-kb/s wireless data transmission. A differential relaxation oscillator (OSC) is for subcarrier generation, and an intermittent dual-mode frequency calibration loop ensures system robustness. Experimental results show that the presented FM-UWB TX successfully generates an Federal Communications Commission (FCC)-compliant UWB signal, with an energy efficiency of 11.5 nJ/bit and an active area of 0.21 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> from a 1-V supply. The 2.25- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{A}$ </tex-math></inline-formula> hybrid BGR and POR achieves a temperature coefficient of 32 ppm/°C, a line regulation of 2.3%/V, a supply-ramp-rate-tolerant power-ON, and brown-out function. The 40- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> XO features a low-frequency inaccuracy of 4 ppm/V. The 40- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{A}$ </tex-math></inline-formula> relaxation OSC provides the reconfigured two-frequency shift keying (FSK) triangular amplitude and frequency. The 2.79–5.18-GHz 0.6-mW ring VCO is capable of providing the phase noise performance of −77 dBc/Hz at the 1-MHz offset, followed by the 0.45-mW PA having the output power higher than −14 dBm and the peak power-added efficiency (PAE) of 29.6%. All these benefit low-power low-cost TX implementation, where the carrier and subcarrier frequencies are calibrated by an intermittent digital loop with omitted power dissipation.

Filtering Push–Pull Power Amplifier Based on Multifunctional Impedance Matching Network

A filtering push–pull power amplifier (PPPA) is presented based on the multifunctional impedance matching network (MIMN), which is constructed by coupled lines and open-circuited transmission lines. Due to the symmetry of designed MIMN, the even-and odd-mode method is employed to analyze the operating mechanisms, which reveal that designed MIMN can achieve high common mode suppression under the even-mode excitation, while provide good impedance transformation and filtering response under the odd-mode excitation. Finally, a filtering PPPA based on the MIMN is designed as well as measured, and the measured operating frequencies are ranging from 1.85 to 2.03 GHz. The measured maximum gain and peak power-added efficiency are 13.9 dB and 57.8%, while the measured upper stopband extends to 4.1f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> with the suppression level of 20 dB.

A 90 GHz Broadband Balanced 8-Way Power Amplifier for High Precision FMCW Radar Sensors in 65-nm CMOS.

We present a W-band 8-way wideband power amplifier (PA) for a high precision frequency modulated continuous wave (FMCW) radar in 65-nm CMOS technology. To achieve a broadband operation with an improved output power for a high range resolution and high distance coverage of FMCW radar sensors, a balanced architecture is employed with the Lange coupler which naturally combines the output powers from two 4-way push-pull PAs. By utilizing a transformer-based push-pull structure with a cross-coupled capacitive neutralization technique, the gate-drain capacitance of the 4-way PA is compensated for the stabilization with an improved power gain. Interstage matching was performed with transformers for a reduced loss from the matching network and minimal area occupation. The implemented balanced 8-way PA achieved a saturated output power (Psat) of 16.5 dBm, a 1-dB compressed output power (OP1dB) of 13.3 dBm, a power-added efficiency (PAE) of 9.9% at 90 GHz and 3-dB power bandwidth was 20.4 GHz (79.2–99.6 GHz).

The instantaneous dissipation in amplifiers class AB and class B

This paper presents analysis of class AB and class B amplifiers dissipation calculated by equals (1) and (2) with MathCad. The figure shows works of push-pull audio power amplifier computer simulations with PSpice Student Version.

ИНТЕРМОДУЛЯЦИОННЫЕ ИСКАЖЕНИЯ В КЛЮЧЕВЫХ ГЕНЕРАТОРАХ КЛАССА D С РЕЗИСТИВНОЙ НАГРУЗКОЙ В РЕЖИМЕ ПЕРЕКЛЮЧЕНИЯ НАПРЯЖЕНИЯ

The development of 5G technologies and the Internet of Things lead to a change in the traditional paradigm of frequency-territorial planning. Indeed, in addition to reducing the distance between base stations of cellular communication, there is a problem of approaching the radio means of mobile devices to them, as well as the problem of uncontrolled convergence of an arbitrary number of radio means on mobile devices. In all cases, intermodulation distortion (name in English technical literature: reverse intermodulation distortion - RIMD) occurs between closely spaced simultaneously operating transmitters. Once in the reception band, they disrupt the normal functioning of radio equipment. Therefore, the requirements for the transmitter's electromagnetic compatibility characteristics are continuously tightened. Class D power amplifiers, in addition to higher efficiency and better quality indicators, may potentially have a lower level of intermodulation distortion. The article deals with intermodulation distortion in previously unexplored class D push-pull voltage switching mode power amplifier with a resistive load. On the developed theoretical approach basis, an analysis was made of the intermodulation distortion levels dependence on the electronic components parameters spread and the circuit operating mode. It is shown that in order to achieve the desired levels of intermodulation distortion, not exceeding -70 dB, it is necessary to ensure the difference in the active elements saturation resistances is not more than 20% and the saturation time deviation from the meander is not more than 2 degrees.

Increase the bandwidth of the power amplifier to 185% of the bandwidth by ferrite transformers

ABSTRACT The motivation of this paper increases the bandwidth of power amplifier to multioctave by matching circuit, which consists of ferrite balun, 4:1 transformers and RC network feedback to make atrade-off between gain and VSWR. So this work discusses the design of a push-pull power amplifier demonstrating over more than a decade bandwidth using matching networks to achieve [30–800] MHz bandwidth. Matching transformer techniques can be used in order to minimise the return loss and increase the gain. Modification of the classical topology, based on inductive compensation of the parasitic capacitance of ferrite, has been proposed and used to design a 1:4 transformer. Practically, miss-match and heating is the main concern for broadband performance of high power amplifier. Coaxial cable and ferrite are also used to dissipate the heat (high temperature) resulting from the amplification power, in addition to installing the board on a cooler with appropriate dimensions, so we get the best match and stability. The simulation results are compared with the measurements. The measured results show that 20.5–17.46 dB of gain, 50.5–47.46 dBm of output power, and 50.9 of drain efficiency are delivered.

Nonlinear distortion of angle modulation signal in output power amplifiers

The output power amplifier is operated in nonlinear mode to increase its efficiency, at which the signal is distorted more. The goal is to analyze effects of nonlinearity on the modulating signal of angle-modulated signal distortions for single-ended and push-pull output power amplifiers with memory and without it. The amplifier characteristic ic(vBE) is preset by the cubic polynomial. The output voltage of memoryless amplifier uout(t) is found by Ohm's law. And in case with amplifier with memory, the output voltage uout(t) is found by Complex amplitude method with a Fourier series of function ic(t). The output voltage uout(t) is represented as the narrowband process with envelope of the waveform U1(t) and initial phase Ф1(t) to determine the angular modulation law Ф1(t) at the amplifier output. The function U1(t) is defined as combination of in-phase А(t) and quadrature В(t) components. The distortion estimate based on Total Harmonic Distortion (THD). The measurement of THD is defined as the ratio of the RMS amplitude of a set of higher harmonic frequencies to the RMS amplitude of the first harmonic. The spectrum of function Ф1(t) is represented a Fourier series. In single-ended memoryless amplifier and non-cutoff mode, the THD decreases as m increases and THD of modulating signal is {37.6; 18.8; 6.3%} at m {0.5; 1; 3}. In cutoff mode, the smallest THD is {15.18; 5.13%} at m {1; 3} as θ = 140o. In push-pull memoryless amplifier and θ = 90o, the THD is {22.2; 11.1; 3.7%} at m {0.5; 1; 3} which is 1.7 times less than in a single-ended amplifier without cutoff. This is due to compensation even-order harmonic of amplified signal at the output of a pushpull amplifier. In this case of memoryless amplifier, the transistor load is a parallel RLC circuit. The distortion decreases under m increases at first (up m is 1.5), but then rapidly increases (from m is 1.7). This is due to increase of the parasitic harmonics level caused by the nonlinearity of the phase-frequency characteristic of RLC circuit. The calculations show that THD of modulating signal is 3.35, 9.02 and 22.88 % at Q = 10 and m {0.5; 1; 3}, respectively. In cutoff mode, the smallest THD is at θ = 90o and it does not depend on θ at large values of m. In push-pull amplifier with memory, the THD is 2.8, 2.5 and 3.0 times less than for a singleended amplifier without cutoff at Q {2.5; 5; 10}, respectively. The results of this paper can be used for the design of signal processing systems.

Compact and Highly Efficient Kilowatt Lumped Push–Pull Power Amplifier for Cyclotron in Radioisotopes Production

This article presents a very compact highly efficient solid-state power amplifier (SSPA) module at kilowatt level in a push-pull architecture. This SSPA is intended to be used as a modular RF source for a 20 kW cyclotron that operates in the low VHF band for radioisotopes production. For a compact design, a lumped LC balun is adopted instead of a traditional ferrite transformer for the 180° phase shift requirement of the push-pull architecture. Lumped harmonic traps are employed as harmonic tuning to achieve higher efficiency. This implementation enables an ultracompact design realized on a 90 mm × 70 mm circuit board. Improved efficiency at reduced output power is achieved through a static supply voltage variation, which gives more than 90% efficiency over a 5 dB output power range. This approach enables considerable energy saving when applied to the whole cyclotron system. The achieved results show that the proposed SSPA with drain supply modulation is a very promising architecture for very high-power RF sources in cyclotrons for radioisotope production.

A Wideband Isolated Real-to-Complex Impedance Transforming Uniplanar Microstrip Line Balun for Push–Pull Power Amplifier

In this article, a three-port uniplanar microstrip line balun is proposed to transform the balanced complex load termination to 50- $\Omega $ unbalanced port impedance. The proposed device is designed based on a symmetric four-port network with an open-ended transmission line inserted between branch lines in the middle of structure. To improve the isolation and match the complex termination, a resistive network is proposed and inserted between the two balanced ports. In addition, the theoretical analysis is carried out for the even and odd mode circuits to expand the bandwidth of the proposed real–complex impedance transforming balun. With the proposed design theory, the impedance trajectory follower splitting and combining baluns are designed for wideband push–pull power amplifier (PPPA). To verify the design concept, first, a real–complex impedance transforming uniplanar microstrip line balun is designed and characterized at 1 GHz. Then, a prototype for the wideband PPPA with impedance trajectory follower microstrip baluns is designed, fabricated, and validated in experiment. For the proposed balun, the simulated and measured results agree well with each other to prove the design concept. From the experimental results, the PPPA with the proposed balun shows a gain of 10.2–12.2 dB, output power of 42.7–44.7 dBm, and a drain efficiency of 59.8%–74.6% within the frequency range of 1.8–2.7 GHz.

Latch-Up Immune Bi-Direction ESD Protection Clamp for Push-Pull RF Power Amplifier

Latch-Up Immune Bi-Direction ESD Protection Clamp for Push-Pull RF Power Amplifier

Common-Mode Stability Test and Design Guidelines for a Transformer-Based Push-Pull Power Amplifier

We report design guidelines for a transformer-based push-pull power amplifier (PA) with a systematic stability test carried out in the complex frequency domain. By detecting the right half-plane zeros of the impedance matrix's determinant, the common-mode (CM) instability in a differential PA were accurately estimated with the established frequencies from the analysis. In the stability test, the parasitic series coupling capacitance of the input transformer and the parasitic inductance from the gate (base) biasing line were identified as the two primary mechanisms of the CM instability in a transformer-based PA contingent on stability. Based on the analysis of the instability mechanisms, useful stabilization methods were proposed and discussed for a robust push-pull PA design with a well-balanced performance. An onboard transformer-based push-pull PA was implemented for the verification purpose, and the effects of parasitic inductance on the stability had been investigated. The simulated and measured results corresponded well with the proposed analysis.

Initial Test of Optoelectronic High Power Microwave Generation From 6H-SiC Photoconductive Switch

High-power photoconductive semiconductor switch (PCSS) working in linear mode can be used for RF generation by modulating the illuminating light. This letter presents a design and initial test of an optoelectronic class B push-pull microwave power amplifier (MPA) using two 6H-SiC photoconductive switches. The initial tests have been conducted with bias voltage of ±2.4 kV, at 80 kW peak laser pulse power, demonstrating that the SiC PCSS working in linear mode can produce microwaves. Then, circuit simulation is conducted to study the factors affecting the electrical efficiency, such as the quantum efficiency, the peak laser pulse power, and the bias voltage. It is speculated that the MPA could output 1 mW microwave power and achieve electrical efficiency of more than 60% with a bias voltage of 15 kV, quantum efficiency of 0.2, and peak laser pulse power of 100 kW.

Design and Construction of an Atmospheric Pressure HF Plasma Source

Atmospheric pressure plasma sources used in many industrial, environmental, light sources, biological, and medical applications. Aiming these prospects, an effort has been remunerated for the design and construction of a cost-effective atmospheric pressure high frequency (30 KHz) plasma source. The major sections include in this source are, (i) DC power suppliers, (ii) A set of Class A push-pull power amplifiers, (iii) Ferrite core high-frequency power transformer, (iv) Impedance matching network, and (v) Electrode design for plasma production. Two power suppliers have been considered; one is a 12V DC for biasing the base of the 2N3055 power, and the other is a 90V DC for biasing the Class A push-pull power amplifier. Class A push-pull power amplifier is chosen because of its high efficiency of about 50% concerning other types of amplifiers. Ferrite core high-frequency power transformer is designed with a turn ratio of 1:3 in order to step up the voltage to a certain level for producing atmospheric pressure plasma. An impedance matching network is designed to transfer maximum power from the source to the plasma load.

Broadband push-pull power amplifier design methodology based on the GaN component base for high-performance nonlinear junction detectors

The paper presents a description of design methodology for wide-band push-pull large-signal power amplifier based on GaN transistor with an output power of more than 10 W for high-performance Nonlinear Junction Detectors, which allows achieving optimal convergence of the theoretical model in practice, as well as increasing the efficiency of the power amplifier while maintaining a linear gain characteristic.

Impedance-matched Planar-antenna-integrated High-efficiency Push-pull Power Amplifier with Center-tapped Transformer for 5 GHz Wireless Communication

Impedance-matched Planar-antenna-integrated High-efficiency Push-pull Power Amplifier with Center-tapped Transformer for 5 GHz Wireless Communication

A Coin-Battery-Powered LDO-Free 2.4-GHz Bluetooth Low-Energy Transmitter With 34.7% Peak System Efficiency

This brief reports a 2.4-GHz Bluetooth low-energy (BLE) transmitter (TX) that can operate against a coin-battery voltage discharging from 1.5 to 1 V, corresponding to a 99.2% battery capacity usage. Specifically, a class-B/C push–pull power amplifier with dual feedback control loops is proposed to dynamically adjust two gate biases, ensuring stable output power and low output HD2. The TX fabricated in 65-nm CMOS occupies a die area of 0.5 mm2 and achieves three stable power levels: $\text{P}_{{\mathbf{ out,H}}}$ (2.7 ± 0.4 dBm), $\text{P}_{{\mathbf{ out,M}}}$ (−0.1 ± 0.6 dBm), and $\text{P}_{{\mathbf{ out,L}}}$ (−2.5 ± 0.8 dBm). At $\text{P}_{{\mathbf{ out,H}}}$ , the system efficiency reaches 34.7%. The 1-Mb/s GFSK output ( ${\mathbf{ m = 0.5}}$ ) and HD2,3 comply with the BLE specifications, and the FSK error is 8.2%. A tiny demo board with an antenna, a crystal, and a coin battery (Nanfu LR44) verifies the feasibility of the TX over-the-air, achieving 27.5 h of continuous operation for a 1-dB reduction of the received power.