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International audience; RF/microwave power amplifier (PA) is one of the components that has a large effect on the overall performance of communication system especially in transmitter system and their design is decided by the parameters of transistor selected. This letter presents a new concept of a wide-band microwave amplifier using scattering parameters that is often used in the radio frequency communication systemas an application of the active integrated antenna[1- 2]. This power amplifier operates from 1.75 GHz to 2.15GHz frequency and it is based on AT-41410 NPN transistor that has a high transition frequency of 10GHz. The proposed Single Stage PA is designed by microstrip technology and simulated with Advanced Design System (ADS) software. The simulation results indicate good performances; the small power gain (S21) is changed between 11.8 and 10dB. For the input reflection coefficient (S11) is varied between -11 and -22.5dB. Regarding the output reflection coefficient (S22) is varied between -13.1 and -18.7dB over the wide frequency band of 1.75-2.15GHz and stability without oscillating over a wide range of frequencies.

In this letter we present a new design of a microstrip microwave PA (power amplifier) for PCS (Personal communication Services/System) applications at 1.85GHz and it is based on AT-41410 NPN transistor that has a high transition frequency of 10GHz. The design process apply in this work is obtained by ADS (Advanced Design System) software. The simulation results show good performances in terms of small and large-signal. The proposed amplifier design achieves a high gain in excess of 12.8dB. For the input reflection coefficient (S11) is below than -33.7dB. Regarding the output reflection coefficient (S22) is below than -29dB. Thus, the unilateral transmission (S12) is less than -19.5dB and for the output power is rise up of 18dBm at 1dB compression point.

A RF-microwave broadband power amplifier using the Si-Bipolar transistor is presented in this work. The power amplifier operates in several frequency ranges 1.70–2.20GHz. Which covers the following bands: DCS (Digital Cellular System) (1710MHz–1880MHz) in Europe, PCS (Personal communication Services/System) (1850MHz–1990MHZ) in the United States, UMTS (Universal Mobile Telecommunication System) (1920MHz–2170MHz). The broadband matching networks of this amplifier consist of microstrip transmission lines. This BPA based on the analysis of scattering parameters, also with using analytical and computer-aided optimization techniques. A typical broadband amplifier has been designed with a nominal power gain of 11.5dB with a maximum deviation of 1dB, covering the 1.70–2.20GHz band. The high gain, good performances for input and output matching networks impedance and stability are achieved.

Amplification is one of the most basic and prevalent microwave analog circuit functions. Wherefore power amplifiers are the most important parts of electronic circuits. This is why the designing of power amplifiers is crucial in analog circuit designing. The intent of this work is to present an analysis and design of a microwave broadband power amplifier by using two stages topology. A two stages power amplifier using a distributed matching network for WiMAX applications is based on ATF-21170 (GaAs FET). The configuration aims to achieve high power gain amplifier with low return loss over a broad bandwidth. The proposed BPA is designed with a planar structure on an epoxy (FR4) substrate. The planar structure is also utilized for getting the good matching condition. The advanced design system (ADS) software is used for design, simulation, and optimization the proposed amplifier. The complete amplifier achieves an excellent power gain; is changed between 28.5 and 20 dB with an output power of 12.45dBm at 1dB compression point. For the input reflection coefficient (S11) is varied between -20 and -42 dB. While the output reflection coefficient (S22) is varied between -10 dB and -49 dB over the wide frequency band of 3.2-3.8 GHz.