Dual-band Power Amplifier Research Articles

Design of dual-band power amplifier based on microstrip coupled-line bandstop filter

This article presents a simple and effective method for designing a dual-band power amplifier (PA). A microstrip coupled-line bandstop filter (BSF) is cascaded with a broadband PA, thus a notched band can be obtained in the wide operating band, realizing a dual-band characteristic of the PA. The simplified real frequency technique (SRFT) is employed to derive a broadband input matching networks covering the requisite frequency band. Appropriate fundamental impedance and second harmonic impedance matching are achieved at the ideal region of the Smith chart. For validation, an experimental prototype is fabricated and tested using a commercial GaN transistor Cree’s CGH40010F. The proposed dual-band PA is operated at 1.95–2.4 GHz and 2.65–3.1 GHz, with 61%–71% measured power-added efficiency (PAE) and 40.5–41.5 dBm of measured output power.

A new design approach for dual-band power amplifiers based on dual-band HCC and bandpass filter

This paper introduces a novel design approach based on the dual-band harmonic control circuit and bandpass filter for dual-band power amplifiers. The circuit schematic of the proposed approach is constructed using four resonators and RFC inductors. The first two resonators are dedicated to controlling the second harmonics, while the third and fourth resonators serve as a harmonic blocker, allowing only the main signals to pass through to the load. Subsequently, all components are replaced by circuits based on microstrip elements, forming the proposed OMN. This OMN includes a novel wideband bias circuit, elliptically coupled resonators, and a new dual-band bandpass filter. To ensure compatibility with the transistor, a compensator line has been integrated. As a result, a dual-band power amplifier has been fabricated and measured at two operating frequencies, 2.1 GHz and 2.91 GHz. The measured values for drain efficiency, output power, and power gain at 2.1 GHz are 75.98%, 37.5 dBm, and 12.5 dB, respectively. Similarly, at 2.91 GHz, these values are 75.73%, 37.24 dBm, and 12.24 dB, respectively.

Dual-Band Power Amplifier With Bandwidth Extension Based on Broadband Harmonic Control Part Dual Transmission Line

This paper presents a dual-band (DB) high-efficiency power amplifier (PA) with extended bandwidth. A novel output matching network (OMN) that integrates harmonic control into DB fundamental matching design is proposed. Bandwidth of the DB PA can be efficiently extended by the OMN presented since it can offer DB broadband harmonic control while maintaining the input impedance at DB fundamentals. By precise control of the characteristic impedance on the part dual transmission line (part-DTL) and the double shunt stub (DSS), these two structures are made equivalent to the series and parallel transmission line (TL) performance at DB fundamentals. Additionally, the part-DTL modulates the input impedance in broadband near DB harmonics to pure reactive, and the DSS optimizes the imaginary part of the input impedance at DB harmonics. For validation, a DB PA is designed and fabricated with a Cree CGH40010F GaN transistor. The fabricated DB PA features the saturated output power of 42.4 dBm and 41.7 dBm with the power-added efficiency of 73.5% and 68.4% at 2.6 GHz and 3.5 GHz, respectively. Specially, the bandwidth of the DB PA is extended to over 300 MHz and 200 MHz.

Design of dual-band power amplifier using bandstop filter and dual-mode bias circuit for multistandard transceiver systems

This paper presents a dual-band power amplifier (PA) using a meandered line bandstop filter (BSF). An important challenge addressed in this design is to achieve proper isolation between the operational bands of the amplifier. The proposed BSF provides isolation and efficiency, effectively separating the output power and power gain between the two operational bands. Additionally, a dual-mode bias circuit is designed to serve as an inductor choke and control the second harmonics for both operating frequencies simultaneously. Two dual-band PAs, utilizing LDMOS and GaN HEMT transistors, have been designed using the proposed output matching circuit, which incorporates the BSF, bias circuit, and compensation circuit. The results obtained from both PAs, employing different transistors, are identical. Based on the presented concepts, a dual-band PA with an LDMOS transistor has been fabricated and measured. The measurements reveal an efficiency of 79.23%, an output power of 39.85 dBm, and a power gain of 14.85 dB at a frequency of 0.7 GHz. Similarly, at a frequency of 1.9 GHz, the efficiency is 77.24%, the output power is 38.22 dBm, and the power gain is 13.22 dB.

Design of High-Efficiency Dual Band Power Amplifier Based on GaN HEMT

In this paper, a novel dual-frequency impedance converter is proposed, and a rigorous derivation process is given. Based on this, a 0.61/2.6 GHz dual-frequency and high-efficiency power amplifier is designed. The joint simulation results show that the designed power amplifier achieves a maximum power added efficiency (PAE) of 68.3% at 0.61 GHz and achieves a saturated output of 41.53 dBm; At 2.6 GHz, the saturated output power is 40.8b dBm, and the maximum PAE is 56.3%. The designed dual-frequency power amplifier has good working performance.

Dual-Band High-Efficiency Power Amplifier Based on a Series of Inverse Continuous Modes With Second-Harmonic Control

This letter proposes a design approach for a dual-band (DB) power amplifier (PA) based on a series of inverse continuous modes (SICMs). The approach possesses a wider fundamental and second-harmonic impedance space compared with inverse continuous class-F, and the dual bandwidths of the DB PA can be improved flexibly. In addition, a variable knee voltage is considered for predicting the output performance of the PA more accurately. A simple impedance control network only for the second-harmonic is exploited to improve PA efficiency. Simulation and measurement results indicate that the fabricated DB PA achieves drain efficiencies of 65%–80.9% from 2.43 to 2.70 GHz, and 65%–76.2% from 3.37 to 3.52 GHz, respectively, and the obtained output power exceeds 10 W in DBs.

Dual-Band Dual-Output Doherty Power Amplifier for Unsynchronized Time-Division Duplexing

Conventional multiband power amplifiers (PAs), when working in time-division duplex (TDD), require the transmit–receive intervals of all bands to be synchronized. This is an undesirable constraint in modern radio base stations. This article proposes a dual-output dual-band Doherty PA (DB-DPA) that enables the loading of one band to be switched on-and-off without impacting the other band in normal transmission. A thorough analysis of the proposed dual-output DB-DPA architecture is presented, and a dual-output DB-DPA prototype operating at 1.4 and 2.6GHz has been designed as a proof of concept. The large-signal measurements of the prototype DB-DPA indicate Doherty behavior at both frequencies with over 56% saturation efficiency and 45% efficiency at 6-dB power back-off (PBO). Furthermore, single-band and concurrent dual-band linearized modulated measurements, using 10-MHz new radio (NR) signals with 6-dB peak-to-average power ratio (PAPR), demonstrate the linearizability of the proposed DB-DPA and its usefulness for unsynchronized TDD applications.

A Dual-Band Dual-Output Filtering Power Amplifier Based on High-Selectivity Filtering Impedance Transformer

In this brief, a novel filtering impedance transformer with good selectivity and high termination impedance is proposed, of which close-formed design equations are derived and effectively verified. Then, a dual-band dual-output filtering power amplifier (PA) operating at 2.4-2.6 GHz and 3.4-3.6 GHz is designed based on the proposed filtering impedance transformer. The dual-band filtering PA contains a diplexer-like output matching network, which can separate two band signals into corresponding output branches. EM-simulated results of the diplexer-like output matching network show that the isolation between the two output ports is better than 30.7 dB. Finally, for demonstration, the dual-band dual-output filtering PA using a packaged 10 W transistor is fabricated, and the measured drain efficiencies are 45.3%-50.2% and 41.7%-53.2% at lower and higher bands, respectively. Also, a good dual-band filtering response is obtained. A good agreement between simulated and measured results is observed.

A Rapid Matching Network Layout Synthesis and Optimization Method for High-Performance MMIC PAs Using Modified Implicit Space Mapping

In this brief, a new systematic approach of matching network (MN) layout synthesis and optimization for power amplifiers (PAs) is proposed based on implicit space mapping (ISM). Commonly, the performance discrepancy between schematic and initial layout is huge, especially for millimeter wave (mmWave) PAs. To address this issue, the proposed modified ISM can shift the optimization work to the circuit schematic simulations by calibrating carefully-selected auxiliary parameters in the circuit based on EM data. To validate the proposed method, an eligible dual-band inter-stage MN layout is rapidly optimized with only 10 runs of EM-simulations, while a corresponding 16/26.5 GHz concurrent dual-band PA is implemented in a 0.15- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaAs pHEMT technology. It exhibits a measured small-signal gain of 21.7/14.1 dB, peak power-added efficiency of 30.2%/40.5%, and saturated output power of 24.8/28.1 dBm with a compact chip size of 2.4 mm2.

Dual-Band High-Efficiency Power Amplifier With Adjustable Transmission Zero

A methodology for designing a dual-band (DB) high-efficiency power amplifier (PA) with adjustable transmission zero (TZ) is proposed in this brief. For achieving a compact topology, the circuit for constructing the adjustable TZ is merged into the output matching network (OMN), and an open stub is shared by the harmonic control network (HCN) and the OMN. For verifying the proposed design method and structure, a prototype operating at 2.1 and 3.5 GHz is designed. The adjustability of the TZ is analyzed, and the frequency range of the TZ is between 2.3 and 3.2 GHz. For verification, the TZ is set to be 2.4 GHz and the DB PA is fabricated and measured. The result shows that the PA achieves the maximum power-added efficiency (PAE) of 68.5% and 64.8% with the output power of 41.0 and 40.4 dBm at 2.1 and 3.5 GHz, respectively. Moreover, the power gain at the TZ of 2.4 GHz is −26.9 dB, which shows a good suppression effect. Therefore, the proposed PA has a good application prospect in wireless communication systems.

Dual band power amplifier with adjustable transmission zeros based on the parallel and series two section transmission line

Dual band power amplifier with adjustable transmission zeros based on the parallel and series two section transmission line

Analytical Dual-Band Matching Approach for Concurrent High-Efficiency Power Amplifiers

In this brief, a dual-band complex impedance transformer is proposed and applied to design a concurrent high-efficiency power amplifier (PA) with a widely spaced frequency. The transmission line parameters of the PA, including dual-band harmonic control network, and dual-band fundamental matching network, are obtained using the derived analytical design formula, which avoids the time-consuming numerical optimization. In addition, the proposed transformer can reduce the probability to use the transmission line with extremely high or low impedance. Simulation and measurement verified that the fabricated dual-band PA achieves the peak power-added efficiency (PAE) of 78.8% and 73.1% with the output power of 42.5 and 40.2 dBm at 0.88 and 2.4 GHz, respectively.

Design of a dual-band microwave power amplifier for wireless communications

In this paper, we present a design of a concurrent dual-band power amplifier operating at 5.8 GHz and 9.4 GHz employing a MMIC technology for wireless communications. The active device used is a 0.25 µm AlGaN/GaN HEMT from WIN Semiconductor, Taiwan. The design goal is to achieve the high-efficiency while still retaining other important metrics including output power and power Gain at concurrent dual frequency bands. The performance of the designed amplifier is evaluated at both small and large signal levels through theoretical analyses and simulation using a Keysight ADS simulator. The developed dual-band amplifier delivered a 47% PAE with 30.5 dBm output power and 12.5 Gain at 5.8 GHz, and a 37% PAE with 30.2 dBm output power and 12.2 Gain at 9.4 GHz.

High efficiency dual-band filtering power amplifier

High efficiency dual-band filtering power amplifier

A 5.5/12.5‐GHz concurrent dual‐band power amplifier MMIC in 0.25 μm GaAs technology

A concurrent 5.5/12.5-GHz dual-band power amplifier (PA) is designed and implemented in a 0.25 μm GaAs pseudomorphic high electron mobility transistor process. The PA is composed of two stages and adopts LC parallel and series networks for dual-band matching. The efficiency of the PA is improved by lowering the drain voltage of the driver stage. Measurement results show that the proposed PA features the maximum small-signal gain of 17.1 and 15.6 dB, the maximum output power of 24.9 and 24.5 dBm, and peak power-added efficiency (PAE) of 35.5% and 35% at 5.5 and 12.5 GHz, respectively. The PA consumes a total DC of 73 mA, and its power consumption is 503 mW. The chip size of the PA is 1.4 × 1.3 mm2 including all testing pads.

A two-dimensional peak-to-average power ratio reduction method based on iterative noise filtering for dual-band power amplifiers

A two-dimensional peak-to-average power ratio reduction method based on iterative noise filtering for dual-band power amplifiers

A novel dual‐band highly efficient power amplifier for 5G applications

This paper presents a novel dual-band highly efficient power amplifier (PA) design for 5G applications. The presented dual-band matching network consists of an impedance tuning network and a dual-band impedance transformer. This structure can not only achieve the precise fundamental and second harmonic control at two 5G bands, but also the excellent dual-band filtering response. Compared with other dual-band PAs, it shows better frequency selectivity and wider bandwidth. For demonstration, a dual-band PA is designed, fabricated, and measured. The measured results display the power added efficiencies of 60% and 47% at 2.5 GHz and 3.5 GHz (bandwidth >150 MHz) under the saturated output power of above 40 dBm, and excellent frequency selectivity with return loss (> 14.7 dB) and stopband rejection (> 25.2 dB).

Dual-Band, Dual-Output Power Amplifier Using Simplified Three-Port, Frequency-Dividing Matching Network

This study presents a dual-band power amplifier (PA) with two output ports using a simplified three-port, frequency-dividing matching network. The dual-band, dual-output PA could amplify a dual-band signal with one transistor, and the diplexer-like output matching network (OMN) divided the two bands into different output ports. A structure consisting of a λ/4 open stub and a λ/4 transmission line was applied to restrain undesired signals, which made each branch equivalent to an open circuit at another frequency. A three-stub design reduced the complexity of the OMN. Second-order harmonic impedances were tuned for better efficiency. The PA was designed with a 10-W gallium nitride high electron mobility transistor (GaN HEMT). It achieved a drain efficiency (DE) of 55.84% and 53.77%, with the corresponding output power of 40.22 and 40.77 dBm at 3.5 and 5.0 GHz, respectively. The 40%-DE bandwidths were over 200 MHz in the two bands.

A Digital Predistortion for Concurrent Dual-Band Power Amplifier Linearization Based on Periodically Nonuniform Sampling Theory

In this article, we propose a novel technique of digital predistortion (DPD) for dual-band power amplifiers (PAs) based on the periodically nonuniform sampling (PNS) theory. In contrast to conventional dual-band DPD (2-D-DPD) models, the proposed periodically nonuniform sampled DPD (PNS-DPD) has only a single input, which can largely reduce the model complexity. We fold the two stimuli with aliasing and feed them to a simple single-band DPD model. The desired predistorted signals are reconstructed from aliased DPD output through the PNS theory. Compared with conventional multi-input models that include numerous intermodulation products of the input signals, the complexity of the proposed single-input PNS-DPD model is hugely decreased. The model coefficients of the proposed PNS-DPD can be easily extracted with conventional direct or indirect learning architecture. We experimentally evaluate the proposed DPD on a test bench and compare it with other DPD techniques in the literature. The implementation complexity can be reduced by over 30%, and the identification complexity is also largely reduced.

Dual-Band Power Amplifier Design at 28/38 GHz for 5G New Radio Applications

This paper presents the design of a dual-band power amplifier (PA) featuring similar performance at 28 GHz and 38 GHz. In the new radio (NR) of the fifth generation (5G) communication system, the inter-band carrier aggregation technique is commonly adopted for data rate enhancement. In such configuration, operation at both bands of the 5G frequency range 2 (FR2) spectrum is often necessary. The stacked-FET topology was adopted for mitigation of the gain roll-off with frequency to achieve similar performance at both frequency bands. Implemented in the commercial 0.15-&#x03BC;m gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) technology, the PA delivered a small signal gain of 18.5/18 dB, an output power at saturation (P_sat) of 28.5/28.2 dBm, and a peak power-added efficiency (PAE) of 39%/36% at 28/38 GHz, respectively. The measurement results have demonstrated great potential of the proposed PA for 5G NR applications.