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.

This paper proposes a multiband microstrip patch antenna covers a multiple operating frequency bands PCS/DCS/LTE/WIFI. The overall dimension of the proposed antenna is 65×67.05mm 2 printed on an FR4 substrate, having 1.6 mm as thickness with a relative dielectric permittivity of 4.4 and 0.025 for loss tangent. The proposed antenna was study and validated by using electromagnetic software's CST-MW. Three bands (1.811-1.828 GHz, 2.631-2.749 GHz and 4.554-5.457 GHz) are achieved by inserting a slot on the top patch and ground. The radiation pattern has acceptable response with low cross polarization at both E-plane and H-plane.

A novel CPW Low pass filter structure using square complementary split ring resonator (CSRRs) is presented in this work. The CSRRs are etched periodically in each ground plane of the CPW line which permit to suppress the spurious response. The low pass filter shows a good rejection in the stop band. The cutoff frequency at-3dB is equal to fc = 5.28GHz. This filter has total area of 35.48x21.16 mm 2 .

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An innovative design of a circular polarization antenna for wireless power transmission is described. The suggested antenna is simply constructed, which consists of a square radiating patch having a slotted center with feeding via a probe and an L-shaped ground plane. The application of this L-shaped ground allows a short connection of the probe power supply to the square patch while retaining a certain elevation from the ground plane to the square patch while using an air layer substrate, thereby allows a proper adaptation of the impedance and an improvement of the bandwidth. The purpose of utilizing the slot in the center of the square patch is to create a circular polarization with an axial ratio value of under 3dB. By means of a through-hole through the vertical L-shaped ground plane, the patch radiating can be readily excited with a probe feed pointing into the same plane as the patch. This approach allows to further improve the bandwidth of the circular polarization. In this way, the CP bandwidth of the proposed antenna is significantly extended by about 10% and a good impedance matching over a wide bandwidth is obtained. The features of the proposed design are investigated and optimized using a 3D electromagnetic (EM) solver. It was found that the proposed antenna covers a broad band of 425MHz, has a 3 dB axial ratio CP bandwidth of approx. 85% of the resonant band, and a gain level of 7.4 dBi or more in the bandwidth of the resonant band. Besides the low cost of the proposed antenna arising from its simplest structure, the resulting performance leads the antenna to be a strong candidate among circularly polarized, single element, and single feed patch antennas.