Sharif Digital Repository

A 6-bit passive phase shifter for S frequency band has been designed in a standard HEMT technology. A new switched-network topology has been proposed for implementing the 5.625 phase shift step which these digital bits are series with each other. We used Advanced Design System (ADS2010) to perform simulations. These digital bits will produce 64 different mode phase shift of -177.15 to +177.15 degree. In all cases simulation obtained less than 1 % error  

In this paper, a noise amplifier circuit in the L-band frequency (lGHz-2GHz) has been designed and implemented through the Advanced Design System (ADS) software. In this circuit, the Cascade technique is utilized in order to amplify the signal. In addition, current reuse, in-ductive feedback, and the inductive square pair techniques are exploited to increase the gain in linearity mode, isolate the signal, and match the input and output networks. There are three objectives for designing this circuit, i.e., increasing the gain, improving the signal stability in the Frequency linearity Bandwidth (L), and enhancement in the NF value. The proposed circuit includes four levels of transistors with... 

The modal analysis of a lossy coupled plasmonic waveguide consisting of two graphene sheets sandwiched among three SiO 2 layers is presented. This analysis extracts even and odd complex propagation constants in addition to even and odd characteristic impedances at various Fermi levels. It is shown that the first even mode is lossless in theory, but other modes are very lossy. Taking into account the losses, first, the transmission line (RLCG) model, including self and mutual elements, is constructed for various Fermi levels and frequencies. Then, the length of a lossy plasmonic directional coupler based on the coupled plasmonic waveguide is designed for a variety of Fermi levels. The... 

A new broadband frequency discriminator is introduced for demodulating the frequency modulated signals in the microwave frequency range. Direct demodulation with no need for tuning the center frequency of the resonance circuits is the most important advantage of the proposed technique. This technique uses the in-phase/quadrature demodulation, in some manner, without using any additional local oscillator for down conversion. Simulation of the proposed demodulator has been done with Advanced Design System software to evaluate and predict the system behavior. A setup based on the proposed method was designed and implemented in order to verify the accuracy of the theory. We tested the proposed...