Broadband, low-noise and power microwave amplifiers

The design of Broadband, Low-Noise and Power Microwave Amplifiers using microstrip softboard technology is investigated. The software program TOUCHSTONE (TM) by EEsof is used extensively as a basic design tool. The characterisation of the GaAs Field Effect Transistors, used for the amplifiers, is carried out. These characterisations are then used by the program in its circuit analysis. A determination of the validity of using the manufacturer's data, for the designs, is determined by comparing it to the measured data. Source-Pull and Load-Pull measurements were performed for the Power GaAs FET characterisation. The noise-parameter device characterisation is carried out in a similar way to that for Load-Pull data. Each amplifier required final tuning adjustments in order to peak the performances. The Broadband Maximum Gain Amplifier had a 10 ± 1.5dB gain over a bandwidth from 2- to 6-GHz. The Low-Noise amplifier achieved 5dB Noise-Figure and 5.4 ± 1. 4dB gain over the 2- to 6-GHz band. The Power amplifier Output Power was 390mW over the 3.7- to 4.2-GHz band. Techniques of broadband matching are investigated, with Double-Stub matching producing the widest bandwidth. A literature survey is presented on aspects of broadband microwave amplifiers, as well as a survey on Computer-aided-design at microwave frequencies and techniques of Large-Signal Transistor characterisation