A high‐efficiency class‐E power amplifier using SiC MESFET

Abstract

This article reports a high efficiency class-E power amplifier using a SiC MESFET, which is designed and tested at 2.14 GHz. To improve output power and efficiency by suppressing harmonic powers, an output matching circuit using the transmission lines is used. From measured results for a single tone, the harmonic power levels are maintained below Ϫ58 dBc at a whole output power level. The peak power-added efficiency of 72.3% with a power gain of 10.27 dB is achieved at an output power of 40.27 dBm. ABSTRACT: It can be shown that a hyperbolic frequency-modulated waveform is Doppler-invariant only when the Doppler factor is a constant number, i.e., the target has a constant velocity and along the direction from the radar to the target. If the target moves in an arbitrary direction, the degradation of the pulse compression caused by the mismatch between the reflected signal and the matched filter may still exist.In this paper, we demonstrate that the Doppler effect caused by the moving target in an arbitrary direction can be approximated by a target with an initial velocity and a constant acceleration along the direction from the radar to the target, which results in a frequency shift in the reflected waveform. Therefore, a bank of matched filters with preselected values of frequency shifts can be utilized to compensate for the Doppler effect. Numerical examples, with target moving in an arbitrary direction, are presented to illustrate this effect, which has been successfully compensated by shifting the frequency response of the matched filter.

4G as a Next Generation Wireless Network

“…The class-E power amplifier with the nominal conditions has been widely used for the RF and microwave applications [14][15][16][17][18][19][20], and many power electronic amplifier's applications [21][22][23]. In these applications, the peak switch voltage and current of the active device is the main challenge, which is required to be solved due its wide applications.…”

“…Therefore, by substituting (20) and (21) into (18), the switch current is obtained as for p < h 2p: (22) The current through the shunt inductor is obtained by substituting (17), (20), and (21) into (16),…”

A high power SiC MESFET class-E power amplifier with an asymmetrical spurline resonator

“…However, in practice the parasitic capacitances and resistances of the device cannot be neglected with the result that the transistor cannot be regarded as an ideal switch model any more. Hence, the maximum efficient operation is limited [7]. …”

“…Furthermore, in the microwave region, microstrip filters are more easily fabricated and suitable applied than the lumped elements filters in PA design. The transmission-line load network topology proposed in [5], which consists of six transmissionlines to suppress five orders harmonics, has been adopted in many class-E PA designs, such as in [6] [7]. The spurline resonator belongs to microstrip filters.…”

Design of class-E power amplifier for zero-current switching operation with MOSFET nonlinear output parasitic capacitance

“…The class‐E power amplifier with the nominal conditions has been widely used for the RF and microwave applications , and many power electronic amplifier's applications . In these applications, the peak switch voltage and current of the active device is the main challenge, which is required to be solved due its wide applications.…”