This chapter discusses the design of MMIC power amplifiers for wireless application by using 0.15 µm GaAs Power Pseudomorphic High Electron Mobility Transistor (PHEMT) technology with a gate width of 100 µm and 10 fingers at 2.4 GHz and 3.5 GHz. The design methodology for power amplifier design can be broken down into three main sections: architecture design, small-signal design, and large-signal optimization. For 2.4 GHz power amplifier, with 3.0 V drain voltage, the amplifier has achieved 17.265 dB small-signal gain, input and output return loss of 16.310 dB and 14.418 dB, 14.862 dBm 1-dB compression power with 12.318% power-added efficiency (PAE). For 3.5GHz power amplifier, the amplifier has achieved 14.434 dB small-signal gain, input and output return loss of 12.612 dB and 11.746 dB, 14.665 dBm 1-dB compression power with 11.796% power-added efficiency (PAE). The 2.4 GHz power amplifier can be applied for Wireless LAN applications such as WiFi and WPAN whereas 3.5 GHz power amplifier for WiMax base station.
TopIntroduction
Modern microwave and radio frequency (RF) engineering is an exciting and dynamic field, due to recent advances in modern electronic device technology and the current explosion in demand for voice, data, and video communication capacity. Prior to this revolution in communications, microwave technology was the nearly exclusive domain of the defense industry and dramatic increase in demand for communication systems for such applications as wireless paging, mobile telephony, broadcast video, and tethered as well as untethered computer networks is revolutionizing the industry.
Microwave technology is naturally suited for these emerging applications in communications and sensing, since the high operational frequencies permit both large numbers of independent channels for the wide variety of uses envisioned as well as significant available bandwidth per channel for high speed communication (Golio, 2001).
This invention relates generally to RF power amplifiers for wireless communications, and more particularly, the invention relates to microwave and millimeter wave integrated circuit (MMIC) power amplifiers having output impedance matching network. This shift has a dramatic effect not only on the design of systems and components, but also on the manufacturing technology and economics of production and implementation as well.
The main purpose of WLANs is used to extend a service provided by a wired network, hotspot. Applications of WLAN can include enabling printers, servers, and routers to be shareable with a wireless equipped computer.
The designed MMIC power amplifiers in this chapter are using 0.15 μm GaAs Power Pseudomorphic High Electron Mobility Transistor (PHEMT) is targeted for wireless applications. The major applications of 3.5 GHz band are wireless internet access, wireless local loop subscriber units/base stations, W-CDMA, WiMax base station and MMDS (Multi-channel Multipoint Distribution Service) whereas for 2.4 GHz band are WLAN, WiFi and WPAN.
Objectives
The main objective of this chapter is to detail out the basic design of MMIC power amplifiers by using 0.15 µm GaAs pHEMT technology for wireless applications at low frequency points which are 2.4 GHz and 3.5 GHz and to analyze power amplifier function, performances and applications.
Power amplifier plays a very important role in transmitter in order to generate and transmit sufficient power signals. A state-of-the-art power amplifier design has to meet the system requirements for high gain, high efficiency and meet the desired output power while the device and process technology of choice plays a crucial role in realizing the performance of the power amplifier.
Software Advanced Design System (ADS) is used to simulate the power amplifier in order to obtain the best performance of the power amplifier. The design methodology for power amplifier design can be broken down into three main sections which are architecture design, small-signal design, and large-signal optimization.
In addition, layout and optimization of the power amplifier is also one critical element in designing the amplifier because layout design is a critical part. It will determine the performance of the power amplifier after fabrication process. Layout design needs to be referred to the layout rules. Signal path using schematic with the transmission line and optimize layout size must be simulated.