Switching-Mode Differential Class-B Amplifier for Phased Array Radar

Abstract

Switching-mode power amplifiers are used in appli-local power density since the input power is divided equally cations where linearity is not critical and efficiency is the utmost into the two transistors to generate the required output power. priority e.g. phased arrays. This paper presents the design of a Low power density is very important for system on chip (SOC) differential class-E amplifier for a phased array radar application in 0.25,m SiGe BiCMOS technology. The operating frequency applications. Therefore, differential topology has been selected range is 2.9 GHz to 3.1 GHz with center frequency at 3GHz. for this design. The design approach of the amplifier which includes damping Radar pulses of a phased array radar are not amplitude circuit, shunt charging capacitor and balun will be described, modulated and thus, it allows to have power amplifiers with Simulations of the design predict an output power and PAE of high efficiency i.e switching-mode power amplifiers. The basic 25.8 dBm and 49 % respectively. The output stage is biased with a 3.3 V at the collector.idea iS to have a nonoverlapping voltage and current waveIndex Terms-SiGe HBTs, phased array radar, switching-forms at the collector of the output transistor. There are two mode power amplifiers (SMPAs), class-E, power added efficiency, configurations suitable for this task: the class-E or class-F power spectrum.amplifier. The class-F amplifier has a better power output capability but the output matching network is complex as it requires the proper harmonic tuning to get the desired RF power amplifiers (PA) are the important and key part output voltage and current waveforms [5]- [6]. On the other of the RF front end in any transmitter. They are used in a hand, class-E amplifier has poor power output capability but wide variety of applications including wireless and satellite much simpler output matching network [7]-[9]. Because of communications, phased array radar, electronic warfare and this reason, class E amplifier is favored. etc. The purpose of a PA is to amplify the input signal In this paper, a highly efficient class-E PA in SiGe based on to a sufficient power level such that the desired signal can differential topology, targeting phased array radar application propagate across some distance and be received at the receiver is demonstrated. The aim is to design a differential class-E end.PA which can deliver 25 dBm output power. The operating Today's most of the research is concentrated on single-frequency range is from 2.9 GHz to 3.1 GHz. ended design implemented in GaN, LDMOS, GaAs MESFET, In the next sections, a class-E amplifier is investigated GaAs HBTs, InP and etc. The compound semiconductor-based followed by single-ended and differential designs and their devices take advantages of their intrinsic material properties simulation results. and offer superior device performance in high-frequency applications such as monolithic millimeter-wave integrated circuits II. THE CLASs-E CONCEPT (MMIC) [1]. However, for low cost, light-weight, h...