Cascode class-E Power Amplifiers Research Articles

Performance of cascode Class‐EF −1 PA with built‐in techniques for UWB radar toward monitoring of patient actions

This work proposes a performance of the cascode Class-EF−1 power amplifier (PA) for UWB radar transmitter. The cascode Class-E PA with built-in techniques overcomes the traditional mismatch and provides good performance of PA. Incurs the resonance and switching effect is observed in cascode Class-E PA that compensates for the parasitic effects and provides a wide-impedance range. While design-II includes negative capacitance and inverse Class-F, which achieves a redundant performance of wide bandwidth and power-added efficiency (PAE). Design-II achieves the redundant performance compared with design-I. Both design-I and design-II are implemented and analysed through simulation and experimental results using RF 65 nm Samsung Magnachip Hynix CMOS process. Design-I achieves a wide-impedance bandwidth ranging from 3 to 11.7 GHz with drain efficiency (DE) and maximum PAE of 80 and 73% at the output power of 26.4 dBm. The global efficiency (GE) and error vector magnitude (EVM) of 70 and 5.2% are also achieving for design-I. The redundant performance in design-II achieves wide bandwidth with operating frequency range of 2–13 GHz with maximum DE and PAE of 85 and 76%. For design-II, GE and EVM are investigated as 68 and 4.9% that could validate the accuracy and robustness of the UWB radar.

Resonance gate bias cascode class-E power amplifier in GaAs pHEMT technology

In this paper, switching behavioural of cascode transistor in class-E cascode structure is improved by resonance gate bias (RGB) technique. The proposed technique can be used to increase supply voltage of a cascode class-E power amplifier (PAs) in order to achieve high output power and efficiency. Output power of class-E PAs are limited due to drain–gate stress caused by the switching transient voltages. The RGB technique relaxes the supply voltage limitation due to breakdown voltage (VBD) of the transistor. In addition, reactance compensation components technique is employed to achieve high-power and wide-band class-E PA. To show validity of the proposed RGB technique, two reliable 1-W high-voltage and high-efficiency class-E PAs are fabricated in a 0.25 μm GaAs pseudomorphic high-electron mobility transistor technology. The 1.8 GHz class-E PA achieves 52% power added efficiency (PAE) and 30.6 dBm output power. The designed 2–3 GHz class-E PA has 45% PAE at output power of 30 dBm.

Experimental Verification of RF Stress Effect on Cascode Class-E PA Performance and Reliability

A cascode class-E power amplifier (PA) operating at 5.2 GHz has been designed using Advanced Design System simulation. RF circuit performances such as output power and power-added efficiency before and after RF stress have been experimentally investigated. The measured output power, power-added efficiency, and linearity after high-input-power RF stress at elevated supply voltage show significant circuit degradations. The impact of hot-carrier injection and gate oxide soft breakdown on cascode class-E PA reliability is discussed.

A 2.45-GHz $+$20-dBm Fast Switching Class-E Power Amplifier With 43% PAE and a 18-dB-Wide Power Range in 0.18-$\mu \hbox{m}$ CMOS

In this brief, the losses in Class-E power amplifiers (PAs) with finite dc-feed inductance are analyzed. This analysis results in practical analytical expressions, which significantly simplify the design and optimization of Class-E PAs. To demonstrate their applicability, the design of a state-of-the-art 2.45-GHz differential cascode Class-E PA in 0.18- CMOS with on-chip dc-feed inductor is presented. By the proposed combination of a dynamic supply voltage and a dynamic cascode bias voltage, high drain efficiency is achieved over a wide power control range, covering from 2.2 up to 20 dBm. At 20 dBm, a power-added efficiency as high as 43.6% was measured. Additionally, fast envelope switching is obtained by adding a single switch to the common-gate nodes of both the Class-E stage and the second driver stage. Measurements show a rise time of merely 2.5 ns and a 73-dB isolation between the on- and off-states. These figures enable ranging applications with submeter accuracy.

A New Common-Mode Stabilization Method for a CMOS Cascode Class-E Power Amplifier with Driver Stage

This paper presents a new common-mode stabilization method for a CMOS differential cascode Class-E power amplifier with LC-tank based driver stage. The stabilization method is based on the identification of the poles and zeros of the closed-loop transfer function at a critical node. By adding a series resistor at the common-gate node of the cascode transistor, the right-half-plane poles are moved to the left half plane, improving the common-mode stability. The simulation results show that the new method is an effective way to stabilize the PA.

A Charging Acceleration Technique for Highly Efficient Cascode Class-E CMOS Power Amplifiers

A cascode configuration in class-E CMOS power amplifiers (PAs) provides high reliability with respect to breakdown considerations. However, it causes a power loss due to the slow transition of a common-gate device from the triode region to the cut-off region. To minimize the power loss of cascode class-E CMOS PAs, we propose a charging acceleration technique, CAT. This method incorporates a capacitive element between the drain and the source of a common-gate device in a cascode configuration, accelerating the charging speed responsible for turning off a common-gate device instantly after a common-source device is turned off and thus minimizing power loss from the device. We compared the performance of the proposed cascode class-E PA to that of the conventional cascode class-E PA using a 0.18- CMOS process. With a 3.3-V power supply, the proposed fully-integrated CMOS PA achieves 30.7 dBm of maximum output power and 45.6% of power-added efficiency (PAE) with a dynamic range of 40 dB at 1.6 GHz. According to measurements, the proposed cascode class-E PA shows improvement in PAE over the conventional class-E PA of between 5% and 9% in a 1.5 to 2.0 GHz range.

Output Power Control in Class-E Power Amplifiers

A technique is presented to facilitate power control of cascode class-E power amplifiers (PAs). It is shown that by controlling the signal applied to the gate of the cascode transistor, the transmit power is changed. The main advantage of the proposed technique is a high 36 dB output power control range (PCR) compared to 20 dB for the traditional approach. This fulfills the requirements of the GSM standard on the PCR at all power levels and all frequency bands (for GMSK modulation). The concept of the cascode power control of class-E RF PA operating at 2.2 GHz with 18 dBm output power was implemented in a 0.18 ?m CMOS technology, and the performance has been verified by measurements. The PA has been tested by a single tone, and by a GMSK modulated input signal.

Analysis and Compensation of the AM-AM and AM-PM Distortion for CMOS Cascode Class-E Power Amplifier

Analysis and compensation methodology of the AM-AM and AM-PM distortion of cascode class-E power amplifiers are presented. A physical-based model is proposed to illustrate that the nonlinear capacitance and transconductance cause the AM-AM and AM-PM distortion when modulating the supply voltage of the PA. A novel methodology that can reduce the distortion is also proposed. By degenerating common-gate transistor into a resistor, the constant equivalent impedance is obtained so that the AM-AM and AM-PM distortion is compensated. An experimental prototype of 2.6 GHz cascode class-E power amplifier with the AM-AM and AM-PM compensation has been integrated in a 0.18 μm CMOS technology, occupies a total die area of 1.6 mm2. It achieves a drain efficiency of 17.8% and a power-added efficiency of 16.6% while delivering 12 dBm of linear output power and drawing 31 mA from a 1.8 V supply. Finally, a co-simulation result demonstrated that, when the distortion of the PA has been compensated, the EVM is improved from −17 dB to −19 dB with an IEEE802.11a-like signal source.