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A three-stage 0.18μm CMOS power amplifier (PA) targeted for 3.1 to 4.8 GHz WiMedia Ultra-Wideband (UWB) system is discussed in this paper. The first and the last stage of the proposed PA are the conventional common source (CS) inductive degeneration while the inter-stage is a common gate (CG) structure with LC matching components. With careful optimization, the inter-stage CG and LC matching components enhances the gain of the amplifier over a wideband range while maintaining a reasonable output power of the proposed PA. Offchip LC components are used to improve the overall input and output return losses of the proposed PA. The proposed PA has a simulated maximum power gain of 19.3 dB, minimum input return loss of 19.7 dB, maximum output return loss of 8.5 dB, reverse isolation of at least 36 dB, maximum output 1 dB gain compression of 10 dBm and power efficiency of more than 30 %, while dissipating a DC power of 20 mW from a 1.5 V supply. Simulation results gathered in this work can serve as a guideline for wideband PAs design, especially in radio frequency (RF) transmitter for mobile devices and consumer products.

Solar trackers rely on a direct-current (DC) motor driver circuit to control the movement of the solar panel. However, conventional DC motor drivers used in solar tracking system do not provide any options for speed and torque control. Hence, the fixed speed of the DC motor leads to either too fast or too slow tracking movement. Usually, the output torque is set to the maximum. If the load (solar panels' weight) is small, the maximum torque is not fully utilized and therefore energy is wasted. So, a fully adjustable DC motor driver for solar tracking system shows great potential in commercialization because highly energy efficient DC motor driver circuit can improves the total efficiency of the solar tracker. Fewer solar panels are needed when they are attached to high efficiency solar tracking system, which will be reflected to lower system cost. Therefore, this enhanced motor driver will bring significant impact to the solar energy industry. The proposed DC motor driver is fully adjustable in term of speed and torque. The speed and torque of the motor is directly proportional to the output voltage and output current of the proposed DC motor driver, respectively. Adaptive controlling of the output voltage and current are possible by installing algorithm in the microcontroller of the DC motor driver and it can be reprogrammed according to the requirement. The speed control makes the solar tracking system to track the Sun more accurately and the torque control saves energy.

A single-stage and cascode stage wideband CMOS low noise amplifier (LNA) that uses the inductive source degeneration network are presented in this paper. The proposed LNAs are implemented in 0.18 μm CMOS technology for a 3-5GHz ultra-wideband system. The proposed single-stage LNA achieves a simulated maximum power gain of +9.25dB, minimum noise figure of 3.2dB, minimum return loss of -6.7dB, input-referred ldB gain compression point of -5.11dBm and input third order intercept point of +3.36dBm while consuming 6.25mW of DC dissipation at a DC supply of V. Simulation results for the proposed cascode stage LNA show a maximum power gain of +12.3dB, a minimum noise figure of 3.2dB, a minimum return loss of -5.1dB, an input PldB of -13dBm and an IIP3 of -4.2dBm, while consuming 10.5mW of DC dissipation with a DC supply of 1.5V. Results obtained from this study can used as reference design for current multi-stage UWB LNAs implementation.