Sharif Digital Repository

This paper presents the design of a 6-bit active digital phase shifter in 0.18-μm CMOS technology. The active phase shifter synthesizes the required phase using a phase interpolation process by adding quadrature phased input signals. It uses a new quadrature all-pass filter for quadrature signaling with a wide bandwidth and low phase error. The phase shifter has simulated RMS phase error of <0.85° at 2.4-5 GHz. The average voltage gain ranges from 1.7 dB at 2.4GHz to -0.14 dB at 5 GHz. Input P1 dB is typically 1.3±0.9 dBm at 3.5 GHz for overall phase states  

In this study, a new isolated high-gain switched-boost DC/DC converter employing two symmetrical switched-boost networks along with a modified control algorithm based on the combination of the pulse-width modulation (PWM) and phase-shift modulation is proposed. Utilising symmetrical switched-boost networks increase the voltage gain of the proposed converter, significantly. Moreover, applying the proposed switching algorithm on the proposed isolated switched-boost DC/DC converter leads to the following advantages: (i) high-voltage gain, (ii) zero voltage switching (ZVS) turn-on of two switches, (iii) ZVS turnoff of two switches and (iv) appearing three controllable parameters (the... 

The lack of turn-off ability makes the spark gap-based Marx generator uncontrollable in terminating the output pulse. In addition, there are some limitations for rise time and voltage gain improvements in the conventional critically-damped Marx design. In this paper, an efficient over-damped design of Marx circuit is proposed, which leads to a shorter rise time as well as a larger voltage gain. A chopping magnetic switch is employed to achieve the desired values of the fall time and full width at half maximum (FWHM). Moreover, adding a DC bias circuit to the magnetic switch provides the ability to adjust the pulse FWHM parameter. Therefore, an output pulse with a shorter rise time, larger... 

A new high step-up boost converter with an active clamp circuit to eliminate voltage spike caused by leakage inductor is introduced in this paper. The introduced power converter has a high voltage gain for variable input voltage from 48V to 80V. Since both main and auxiliary switches turn on with zero voltage switching (ZVS) and all the diodes turn off under zero current switching (ZCS) condition, switching losses and EMI noises are strongly degraded. Therefore, the converter's efficiency is improved significantly. Simulation results show a 96.4% peak efficiency and 95.4% average efficiency. The proposed topology is suitable for low-input-voltage and low-output power applications such as... 

An inductorless low noise amplifier (LNA) with active balun for digital TV (DTV) applications is presented. The LNA exploits a noise cancellation technique which allows for simultaneous wide-band impedance matching and low noise design. The matching and amplifier stages in the LNA topology perform single-ended to differential signal conversion with balanced output. The second and third-order nonlinearity of the individual amplifiers as well as the distortion caused by the interaction between the stages are suppressed to achieve high IIP2 and IIP3. A method for intrinsic cancellation of the second-order interaction is employed to reduce the dependence of the IIP3 on the frequency spacing...