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This article presents partial result of the PhD thesis on the topic of the Doherty power amplifiers. The design of high-efficiency 3way Doherty amplifier with the use of Wolfspeed CG2H40010 transistors is presented. A newly invented 3-way power splitter architecture is also shown. The proposed splitter and the properties of GaN HEMT technology enable the design of the Inverted 3-way Doherty amplifier...
In mobile phone systems, the 4th generation is widely prevailing in 2017, and in 2020, it is expected that the 5th generation (5G) will start to prevail. In both generations, a linear power amplifier is used. The linear amplifier, in spite of the name, operates non-linearly. Here, non-linear operations of the linear amplifier and their effects on the linearity characteristics are stated.
This paper presents a 300 W GaN power amplifier operating in the LTE band 7 (2.62∼2.69 GHz). From the loadpull simulation, optimum impedances of the GaN HEMT at the fundamental frequency and the second harmonic frequency are extracted for a maximum output power. The matching circuits that give the nearly optimum second harmonic impedances are implemented on a titanate substrate with a high dielectric...
This paper describes a wide dynamic-range and accurate complex-impedance detector for adaptive power amplifier load tuning systems. The detector IC, fabricated in a 130 nm SOI technology, consumes 7mA under 2.5V supply voltage. It can handle LTE signals with an input power from 0 dBm up to 40 dBm thanks to its variable attenuator system. System level measurements show that the detector has a very...
This paper presents a 2.3GHz – 2.7GHz broadband CMOS FDD/TDD LTE Band 7. 38, 40 and 41 power amplifier (PA) fully integrated with a fast envelope tracker (ET) on a single 0.18µm CMOS die. The PA and the tracker achieve a 37% overall efficiency for 26.5dBm and −39dBc ACLR1. The entire design including the input/output match uses an active silicon area around 2.7mm2.
A novel modeling technique is proposed to improve the Radio over Fiber (RoF) modeling and the Predistorter identification. This method is based on an orthogonal basis composed by Zernike polynomials, whose features guarantee numerical stability, a problem present in the classical polynomial model based on Volterra series. The measurements have been carried out with a LTE downlink signal with a bandwith...
In this paper, two multi-basis weighted memory polynomial models are proposed for radio frequency power amplifiers' behavioral modelling. In these models, the conventional memory polynomial function of the generalized and hybrid memory polynomial models is replaced by a weighted version of it. Experimental validation was performed on a power amplifier prototype exhibiting strong memory effects, and...
A novel multi-band multi-mode (MMMB) power amplifier (PA) structure for GSM/TD-SCDMA/LTE cellular applications, is presented. For good harmonic suppression and high integration density performance, a Class-E PA and linear PA cores are employed with only two output paths for low band (LB) and high band (HB), respectively. The selections of modes (2G/2.5G/3G/4G) and working condition of each PA core...
A high efficiency multi-mode class-E outphasing RF power amplifier with a passive combining circuit is presented. The multi-mode PA improves efficiency at lower power levels by switching ON and OFF individual branches and using Efficiency Enhancement Circuit (EEC). The proposed power amplifier is designed in 45nm CMOS technology. The PA delivers 31.6 dBm peak output power at 2.4GHz with 49.2% drain...
This paper reports on a 27.5 dBm wide band high efficiency InGaP/GaAs HBT two stage module operating at 1805 to 2170MHz for LTE small cell base station carrier aggregation applications. It uses a high linearity, low thermal resistance HBT flip chip process developed by Qorvo. The Psat of this device reaches 35dBm, with a gain of around 31dB, and a PAE of 55%. With a DPD (digital pre-distortion) system,...
A high power, efficient, linear and thermally stable 5 watts power amplifier design is shown in this paper as a candidate for modern wireless industry. The designed amplifier uses GaN HEMT biased in class-AB mode and operates in LTE communication band (2.110 GHz to 2.170 GHz). Procedure adopted to achieve a realizable and first-pass design is discussed. To improve reliability, a low inductance ground...
This paper presents a dual-band power amplifier (PA) for LTE applications at 1.8 GHz and 2.6GHz in TSMC 0.18 μm CMOS technology. The proposed PA consists of a two-stage cascode structure comprising a driver stage and power stage. The driver stage employs a RC feedback and resistive feedback. The feedback technique is used to improve the bandwidth. The power stage employs a diode linearizer help to...
With the practical use of the 4G LTE, the need for a versatile power amplifier (PA) increases. The conventional envelope sigma-delta modulation (ESDM) PA is a promising technique for future soft radio, although it has some problems with noise and coding efficiency. This paper describes the application of the technique of single-level ESDM with a thinning out process applied only to the higher part...
The demand for higher data rated has lead to the utilization of both higher frequency bands, where power amplifiers (Pas) are inherently less linear, as well as carrier aggregation (CA) where linearity requirements are more stringent. In addition, cost reducing tactics for large volume applications naturally lead to CMOS based PAs which are less linear than the commonly used GaAs PAs. Envelope tracking...
This paper reports the first high power LDMOS amplifier solution which breaks the 50% drain efficiency barrier at 8 dB output back-off (OBO) for 2.1 GHz cellular application. Targeted for fourth-generation (4G) LTE communication systems, the work seeks to achieve high average efficiency when used with OFDM or other high peak-to-average ratio (PAR) digitally modulated signals. A power transistor, the...
In this paper, a 28nm radio frequency (RF) complementary metal-oxide-semiconductor (CMOS) power amplifier (PA) is presented. It was designed to meet 3GPP TS 36.101 V10.10.0 requirements for Long Term Evolution (LTE). The design was tested on board and has full onchip matching. Furthermore, the biasing for class-AB is also implemented on chip. The maximum gain is more than 15 dB until 0dBm input power...
This paper studies the impact of bandwidth limitation on the linearity of multilevel LINC (ML-LINC) transmitter. By using the signals with discrete levels for characterisation, both amplitude and phase dispersions around levels can be observed, which result in the degradation of system linearity. It is also shown that improvement on both adjacent channel leakage ratio (ACLR) and error vector magnitude...
This paper studies the impact of bandwidth limitation on the linearity of multilevel LINC (ML-LINC) transmitter. By using the signals with discrete levels for characterisation, both amplitude and phase dispersions around levels can be observed, which result in the degradation of system linearity. It is also shown that improvement on both adjacent channel leakage ratio (ACLR) and error vector magnitude...
This article introduces a coupled planar antenna which is made of a driven monopole antenna and a parasitic element fed through a via. These elements are etched in a no-ground part, which is small compared to the Printed Circuit Board (PCB) size. The antenna has several resonant modes enabling three wide operating bands, which respectively cover the LTE700/GSM850/900, GSM1800/1900/UMTS, LTE2300/2500/2700...
This paper presents a new approach to improve the accuracy of power amplifier or transmitter characterisation. Compared to traditional characterisation, an iterative characterisation approach using realistic excitation signals is introduced. Based upon this approach, more accurate nonlinear behaviour for AM/AM and AM/PM can be measured. A memoryless piecewise digital predistortion (DPD) model using...
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