فهرست مطالب ساحل جواهرنیا

Today, one of the most important issues in mobile communication systems is having a long battery life. Therefore, the problem of power consumption appears as one of the challenges in the field of designing high frequency circuits. In a high-frequency receiver, due to the placement of the low-noise amplifier in the first stage of the receiver, this amplifier is very important to determine the linearity and noise in the entire receiver. In this paper, a low noise amplifier has been designed for the GPS standard. Compared to previous works, the noise of the amplifier has been reduced somehow, and its power consumption has reached its minimum value. The working method is that in common source amplifiers, their source base is connected with an inductor, which results in improving circuit noise. But the used inductor occupies the surface of the chip. Therefore, in this article, the existence of the inductor in wire-bond is used, and the noise of the amplifier is reduced, and the occupied area of the chip is not increased. Gain, NF, input impedance of the proposed amplifier have been calculated in the best case and the worst case in the corners of FF and SS, and it can be seen that in this article, compared to the previous works, very favorable results have been obtained.

Photon crystals are on of the most common structures for designing and implementing electronic optical circuits. The photon gap band is of great importance in these structures. The most common mathematical methods for analyzing and calculating photon band diagrams and extracting the forbidden photon band of photon crystals is the flat wave expansion method. This method has many complexities that require special commercial software to perform its calculations. In two-dimensional photonic crystals, two parameters in the photon band are affected, which are the refractive index of the dielectric material and the ratio of the radius of the holes to the constant of the crystal lattice (r / a). In this paper, using mathematics and linear regression, simpler relations for extracting the photon band range of photon crystals are presented. Comparison of the results obtained from the relations with the results obtained with BandSOLVE software for photonic crystals shows that the maximum difference between the two calculation methods for fl and fu is 0.007 and 0.028, respectively, and the average difference is , respectively 0.004 and is 0.01.

Refractive index sensors are one of the most widely used sensors in the bioelectronics and optoelectronics industries. The use of materials and structures that can detect the refractive index of unknown materials has important applications in biochemistry and medical engineering. In this paper, a polymer-based dual-core photon crystal fiber is introduced to measure the refractive index of a fluid. The size of the holes of the analyte cores and the light-transmitting solid core are engineered to be able to pass the main single mode. Due to its cheapness, high mechanical ability and ease of fabrication, the photon crystal fiber substrate is made of PMMA polymer. After simulating the structure and using the existing mathematical relations and examining the diffusion modes, for the complete transfer of light from the solid core to the core of the analyte channel, a fiber length of 0.13 cm has been obtained. The simulation results show that for a refractive index of 1.44, a sensitivity value of 1000  and a detection limit can be achieved by this sensor. All simulation steps in the field of FDTD are obtained in Lumerical software.