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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.

International audience; This paper presents a 1.80GHz class-A Microwave power amplifier (PA). The proposed power amplifier is designed with single-stage architecture. This power amplifier consists of a bipolar transistor and improved by Collector-Feedback Biasing fed with a single power supply. The aim of this work is to improve the performance of this amplifier by using simple stubs with 50Ω microstrip transmissions lines. The proposed PA is investigated and optimized by utilizing Advanced Design System (ADS) software. The simulation results show that the amplifier achieves a high power gain of 13dB, output power rise up to 21dBm and good impedances matching ;For the input reflection coefficient (S11) is below than - 46.39dB . Regarding the output reflection coefficient (S22) is below than -29.898dB, with an overall size of about 93 x 59mm² .By the end; we find that this power amplifier offers an excellent performance for DCS applications.

Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2.

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.