Broadband High-efficiency Power Amplifiers Research Articles

Design of broadband power amplifier based on loop-shaped filter matching structure

A method for designing a broadband high-efficiency power amplifier (PA) based on a novel loop-shaped filter matching structure is proposed in this paper. By combining a power amplifier matching circuit and a loop-shaped filter structure, a broadband high-efficiency PA based on a new harmonic matching structure is realized. The novel loop-shaped filter can control the second and third harmonics in a wide frequency range and has a specific control effect on higher-order harmonics, which can further expand the bandwidth of class-F PA and improve efficiency. To verify its feasibility, a power amplifier with a bandwidth of 1.6 GHz-3.4 GHz, a saturated output power greater than 41 dBm, a drain efficiency of 65% -72% with a gain greater than 10dB is designed and fabricated using GaN HEMT CGH40010F transistor.

A broadband high-efficiency GaN-based power amplifier using an improved continuous mode

This paper proposes a broadband high-efficiency power amplifier using an improved continuous mode design. A tuning parameter is introduced into the current expression of the drain to purposely introduce more sine components. These sine components extend the impedance space of the traditional continuous mode, provide greater flexibility in the design of the broadband output matching network, thereby widening the operating bandwidth. Moreover, since no overlap between the current sine components and the voltage cosine components are produced, these sine components do not degrade the PA's efficiency, unlike traditional continuous-mode PAs that often trade efficiency for bandwidth. To validate our approach, a broadband high-efficiency power amplifier is designed using GaN HEMT. Measurements indicate that output power is between 40.8 dBm and 42.3 dBm, and the drain efficiency varies from 72.7%-81.8% in 1.5-2.5 GHz, while the gain is between 11.3 dB and 13.0 dB in the same frequency range.

Design of a broadband high‐efficiency power amplifier through mixed strategy

This letter presents a mixed strategy to design broadband high-efficiency power amplifiers (PAs), where the mixed continuous mode PA provide theoretical impedances. Furthermore, only a single one-stage coupler circuit with appropriate terminals is exploited to satisfy the fundamental and second harmonic impedances requirements necessary for mixed continuous mode PA realization. Combination of mixed modes PAs' desired impedances and the coupler's impedance frequency modulation trajectory, the available design frequency band can be determined. For validation, a broadband high-efficiency PA covering the frequency range 0.4–3.0 GHz is designed and then fabricated using a CGH40010F transistor. Measured results indicate that the implemented PA can deliver saturated output power of 40.2–42.7 dBm across the frequency range 0.4–3.0 GHz, with drain efficiency of between 60.4% and 74.5%.

High‐efficiency broadband power amplifier design via ideal de‐embedding and direct compensation of GaN‐HEMTs parasitics

In this work, a design approach for broadband high-efficiency power amplifiers is presented. The proposed technique is based on deductive de-embedding of the nonlinear parasitics of packaged GaN-HEMT devices. A new transistor parasitics equivalent network is proposed that utilises a model-based extraction flow. A simple two-element compensation network is then used to accurately compensate the extracted nonlinear device parasitics; this enables optimum load resistance to be presented to the device current generator using a real-to-real matching network. In order to validate the proposed concept, a single-ended Class-AB power amplifier is designed and fabricated using a Wolfspeed 25-W GaN HEMT ‘CGH40025F’ transistor. At a centre frequency of 2.35 GHz, a fractional bandwidth of 55% is achieved. The measured average drain efficiency and power gain of the designed power amplifier are 71% and 10.4 dB, respectively.

Design of Continuous Class-B/J Power Amplifier Based on Mirrored Lowpass Filter Matching Structure

This paper proposes a methodology for designing broadband class B/J power amplifier based on a mirrored lowpass filter matching structure. According to this filter theory, the impedance of this design method is mainly related to the cutoff frequency. Series inductors and shunt capacitors filter out high frequencies. The change of input impedance with frequency is small in the passband. Which can suppress higher harmonics and expand bandwidth. In order to confirm the validity of the design method, a broadband high-efficiency power amplifier in the 1.3 - 3.9GHz band is designed and fabricated. Measurement results show that the output power is greater than 40.5dBm, drain efficiency is 61.2% - 70.8% and the gain is greater than 10dB.

Compact broadband high‐efficiency power amplifier using terminated coupled line filter matching network

This article presents a compact broadband high-efficiency power amplifier (PA) with a filtering structure. Unlike the cascaded filter behind the traditional PA, the proposed cascaded branch load coupling microstrip line structure is used to design the output matching network (OMN) of the PA. It plays the roles of impedance matching and filtering, which is called a filtering OMN, the overall size of the circuit will be reduced. Two coupled microstrip lines cascaded are used to extend the working bandwidth, and a microstrip line is loaded to the port of the coupled microstrip lines to ensure high selectivity and good out-of-band performance. For verification, a broadband high-efficiency PA is designed and manufactured by using CGH40010F GaN HEMT. Measurements demonstrate that in the range from 1.2 to 3.6 GHz, the saturated output power is from 39.8 to 41.8 dBm, the drain efficiency (DE) with a 62%–73%, and the gain is between 9.9 and 11.7 dB.

A Broadband High-Efficiency Hybrid Continuous Inverse Power Amplifier Based on Extended Admittance Space

A novel hybrid continuous inverse power amplifier (PA) that is constituted by a continuum of PA modes from the continuous inverse class-F to the continuous inverse class-B/J is proposed, and a detailed mathematical analysis is presented. The fundamental and second harmonic admittance spaces of the hybrid PA proposed in this article are analyzed mathematically. By introducing the phase shift parameter into the current waveform formula of the hybrid continuous inverse PA, the design space of the fundamental and second harmonic admittance is expanded, further increasing the operating bandwidth. The efficiency of the amplifier under different parameter conditions is calculated. In order to verify this method, a broadband high-efficiency PA is designed and fabricated. The drain voltage and current waveforms of the amplifier are extracted for analysis. The experimental measured results show a 60.7–71.5% drain efficiency across the frequency band of 0.5–2.5 GHz (133% bandwidth), and the designed PA can obtain an 11.8–13.9 dB gain in the interesting frequency range. The measured results are confirmed to be in good agreement with theory and simulations.

Design of a broadband high-efficiency power amplifier by using a simple method

Design of a broadband high-efficiency power amplifier by using a simple method

Broadband High Efficiency Power Amplifier with Compact Matching Network

Broadband High Efficiency Power Amplifier with Compact Matching Network

A Broadband Doherty Power Amplifier With a New Load Modulation Network

In this paper, we proposed a new load modulation method to improve bandwidth and efficiency at output power back-off (OBO) of the Doherty Power Amplifier (DPA). The quarter wavelength transmission line behind the combination point of the impedance inverter was replaced with a dual-frequency matching circuit to matche the impedance value of the combination point to the load impedance in this method. The dual-frequency matching was used to compensate for the frequency dispersion effect that occurs in the traditional impedance inverter network and to a certain extent solves the bandwidth limitation of the Doherty power amplifier. To verify the proposed theory, a broadband high-efficiency power amplifier was designed and manufactured for 5G mobile communications. Measurement results show that the designed DPA is in the range of 2.4-3.7GHz, the saturated output power is above 42dBm, the saturated drain efficiency is 61.2%-68.4%, and the 6dB back-off efficiency is 49.7%-61.4%.

A Broadband High-Efficiency Power Amplifier by Using Branch Line Coupler

This presents a broadband high-efficiency power amplifier (PA). The branch line coupler is used to design the output circuits of the PA. By appropriately selecting the impedance conditions of terminal ports, the branch line coupler can not only realize impedance conversion but also realize harmonic impedance control. Two-stage couplers are exploited to expand the working bandwidth. To verify the effectiveness of the proposed method, a broadband high-efficiency PA is designed and fabricated by using CGH40010F. Measurements demonstrate that the saturated output power is from 41.0 to 42.5 dBm, the drain efficiency is between 64% and 75%, and the gain is from 10.2 to 11.5 dB.

Broadband High-Efficiency Power Amplifier With Quasi-Elliptic Low-Pass Response

This paper presents a broadband high-efficiency harmonic-tuned power amplifier (PA) with quasi-elliptic low-pass responses. A combination of continuous Class-F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> and extended continuous Class-F PA modes is employed to significantly expand the design space. A quasi-elliptic low-pass matching network is proposed, which can realize a broadband impedance matching in the predefined optimal impedance region desired by the combination of PA modes. Furthermore, two transmission zeros are generated near the passband, exhibiting high skirt selectivity and providing rapid impedance transition from the passband to the stopband. A wide stopband covering up to the third harmonic is achieved which shows good harmonic suppression. Design procedures of the proposed broadband PA are presented. To verify the proposed methodology, the broadband PA is fabricated and measured. The implemented PA achieves a bandwidth of 145.2% from 0.5 to 3.15 GHz. Over this frequency range, the drain efficiency is measured as 58–74.9% with the output power of greater than 39.03 dBm and a large signal gain ranging from 8.43 to 15.67 dB. A wide stopband is realized from 3.4 to 10 GHz, showing excellent quasi-elliptic low-pass responses. The measured adjacent leakage ratios (ACLRs) using a 20-MHz LTE signal with digital pre-distortion are below −45.06 dBc.

Design of broadband high-efficiency power amplifier based on elliptic low-pass and band-pass matching network

Design of broadband high-efficiency power amplifier based on elliptic low-pass and band-pass matching network

Design of Multioctave High-Efficiency Power Amplifiers Using Stochastic Reduced Order Models

This paper presents a novel general design method of frequency varying impedance matching. The method is applied to design of a broadband high-efficiency power amplifier (PA). The proposed method defines the optimal impedance regions of a PA at several frequency sections over the operational frequency band. These regions contain the impedances that can achieve a high output power and a high-power added efficiency (PAE) simultaneously. A low-pass $LC$ -ladder circuit is selected as the matching network (MN). The element values of the MN can be obtained using a synthesizing method based on stochastic reduced order models and Voronoi partition. The MN provides desired impedance in the predefined optimal impedance region at each frequency section. Thus, optimal output power and PAE of the PA can be achieved. To validate the proposed method, two eighth-order low-pass $LC$ -ladder networks are designed as the input and output MNs, respectively. A gallium nitride (GaN) HEMT from Cree is employed as the active device. Packaging parasitic of the transistor has been taken into account. A PA is designed, fabricated, and measured. The measurement results show that the PA can achieve P1 dB PAE of better than 60% over a fractional bandwidth of 160% (0.2–1.8 GHz). The output power is 42–45 dBm (16–32 W), and the gain is 12–15 dB. The performance of the PA outperforms existing broadband high-efficiency PAs in many aspects, which demonstrates the excellence of the proposed method.

Design of Broadband High-Efficiency Power Amplifiers Based on the Hybrid Continuous Modes With Phase Shift Parameter

The hybrid continuous modes are constituted by a continuum of power amplifier (PA) modes between class-J and continuous class-F. In this letter, a phase shift parameter is introduced in the voltage waveform formula of the hybrid continuous modes to generate complex fundamental and harmonic load impedances, leading to a further extension on the operation bandwidth. Based on the proposed theory, a gallium nitride PA is designed and fabricated over the frequency band of 1.2–3.6 GHz. The measured results show a 60%–72% drain efficiency at a saturated power of 40–42.2 dBm. In addition, when driven by a 20-MHz long-term evolution signal with a peak-to-average power ratio of 7.4 dB, the proposed PA obtains an adjacent channel leakage ratio of −35 dBc at an average output power of 35 dBm at 2.3 GHz.

Design of broadband high-efficiency power amplifiers based on the harmonic-tuned

Design of broadband high-efficiency power amplifiers based on the harmonic-tuned

Design of a Novel Wideband High Efficiency CCF PA

In this article, a novel approach for the design of broadband high-efficiency power amplifiers (BHPAs) is presented. The method is to simplify the process of synthesizing a wideband output matching network by realizing harmonic tuning and fundamental matching separately. First, the second and third harmonic load impedances are calculated based on the theory of Continuous Class-F Mode. Then, a novel wideband harmonic-suppressing network is obtained by using microstrip radial stubs which is not affected by the adjacent fundamental matching circuit. The proposed PA using a 10-W Cree GaN HEMT device achieves a measured result of a fractional bandwidth of 30.4% from 1.95 to 2.65 GHz, with 60.9–81.6% drain efficiency, 60–79.9% PAE and 39.7–41.7 dBm output power throughout the operating band. As shown in the design process, simulated analyses and measured results, the proposed idea makes the design of the harmonic load network much easier and more accurate. It is generally more feasible, compared with some of the existing methods which are difficult to realize the fundamental and harmonic wave controlling at the same time, especially at higher frequencies. And this method can be widely applied in the BHPA design and modern wireless communication systems.

Bayesian Optimization for Broadband High-Efficiency Power Amplifier Designs

This paper proposes a novel, optimization-oriented strategy for the design of broadband, high-efficiency power amplifiers (PAs) using Bayesian optimization (BO). The optimization algorithm optimizes the drain waveforms by maximizing the fundamental output power while minimizing the harmonic and dissipated components. The optimization process is automated using simulation software. Circuit-based BO and electromagnetic-based (EM-based) BO are applied to design 10 and 30 W PAs. The 10 W PA designed using circuit-based BO achieves a drain efficiency higher than 60% with output power greater than 39.8 dBm from 1.5 to 2.5 GHz, while the 30 W PA designed using EM-based BO offers a drain efficiency higher than 57% with output power greater than 43.8 dBm across the band. Upon comparison of results, it is revealed that the proposed strategy outperforms a commercial electronic design automation (EDA) software's built-in optimizer, thus demonstrating that the EM-based BO is well-suited to the challenge of high power designs.

Multispectrum Signal Transmitters: Advances in Broadband High-Efficiency Power Amplifiers for Carrier Aggregated Signals

The growing demand for broadband mobile access drives the deployment of sophisticated and increasingly spectrum-efficient modulation techniques and access technologies resulting in communication signals with highly varying envelopes and increasing peakto-average power ratios (PAPRs). These communication signals call for advanced transmitter architectures and design techniques. This is particularly the case for the constituent radio frequency (RF) power amplifiers (PAs), which are required to amplify communication signals efficiently while maintaining signal quality and minimizing out-of-band emissions in adjacent channels. The Doherty [1] technique has been successfully applied to develop highly efficient solid-state PAs for wireless communication applications. Benefiting from recent advancements in laterally diffused metal oxide semiconductors (LDMOSs), and taking advantage of the advent of gallium nitride (GaN) technology, Doherty PA (DPA) demonstrators with average drain efficiencies approaching 50% were reported in [2]-[4]. Unfortunately, the underlying narrow bandwidth of these demonstrators currently restricts their use to infrastructure supporting third-generation (3G) wireless networks. Communication signals required by the 3G Partnership Project (3GPP) specifications for long-term evolution (LTE) will have to utilize carrier aggregation to meet the need for transmission bandwidth. Carrier aggregation refers to the use of more than one spectrum portion to deploy multiple component carriers to yield aggregated channels of wider transmission bandwidth (up to 100 MHz). Figure 1 illustrates the three carrier aggregation scenarios that are envisaged: 1) intraband contiguous carrier aggregation (contiguous component carriers aggregated in the same operating band), 2) intraband noncontiguous carrier aggregation (noncontiguous carriers aggregated in the same operating band), and 3) interband carrier aggregation (carrier aggregation of component carriers in different operating bands that may be contiguous or noncontiguous within each band).

Design of Broadband High-Efficiency Power Amplifiers Based on a Series of Continuous Modes

In this letter, a series of continuous modes for designing broadband high-efficiency power amplifiers (PAs) are proposed, which extend the continuous mode concept. The impedance solutions space based on these modes offer a greater freedom for realizing broadband high-efficiency PAs. To verify this theory, a high-efficiency PA over a 54.5% bandwidth from 1.6 to 2.8 GHz is designed. The simulated results show that the fundamental impedances in this PA are found to be in good agreement with the calculated ones. Moreover, this PA delivers average output power of 14.2 W with an average drain efficiency of 75.7% in the target band.