The use of power combination techniques in amplifier design is the simplest and easiest way to obtain high power and wide bandwidth. For example, balanced amplifiers are usually used in microwave integrated circuits for high power and broadband components. In balanced ampifire design, two similar single-ended amplifiers are in parallel connected via two quadrature couplers. It is required a large number ofidentical components for use in transmitter/receiver phased array radars, and communication systems. Therefore, the balanced amplifier is the best option to obtain predicted targets. In this thesis, several microwave power combiners/dividers such as Lange coupler, Wilkinson coupler, and Branch-Line coupler and also balanced low noise amplifier are designed and simulated in X-band between 9GHz and 11GHz, and their results have been compared to a single-ended low noise amplifier. The balanced amplifier with two-stage Wilkinson power divider has been fabricated. The fabricated amplifier has an associated gain of 12±0.5 dB, and a good input/output matching in the whole frequency band. Additionally, the measured results indicate that the amplifier has a noise figure of 1.023 dB at 10GHz. As well as, small signal modeling of the transistor that is used for amplifier design is evaluated with an analytical procedure. Then the circuit model parameters are accurately optimized using optimization approaches such as particle swarm optimization, random, gradient, random and gradient, simulated annealing, and genetic algorithm accurate values achieved. In addition, these results are compared to measured results, which show good agreement. Finally, Pospieszalski model is used to estimate gate and drain noise temperatures with the extracted small-signal circuit model. Keywords: Balanced amplifier, low noise amplifier, Lange coupler, Wilkinson coupler, Branch-line coupler, Signal and noise modeling