The Frequency Selectıve Surface Applıcatıons On Cpu And Gpu


Thesis Type: Postgraduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2015

Student: İFAKAT MERVE BAYRAKTAR

Supervisor: NURSEL AKÇAM

Abstract:

2,4 GHz, 3,6 GHz, 4,9 GHz, 5 GHz and 5,9 GHz frequency bands are WLAN channels specified in the IEEE 802.11 protocol. The devices are often used at the 2,4 GHz frequency. But the efficient use cannot be achieved in most cases due to limited number of channels and many of these devices working at this frequency. This situation can be prevented by using the 5 GHz frequency. The efficient use can be achieved owing to enough number of channels and few devices working at this frequency. FSS band stop filter has been designed to prevent initiatives and stop inappropriate waves at the 5 GHz frequency bands in this context. Shielding effectiveness of FSS has been analyzed at the 5 GHz frequency bands with this design. When the electromagnetic waves are coming to a conductive surface, currents are induced on the conductor. Scattering are happened because of these induced currents. First off all, the expression of the wave equations are written. Then, the scattered wave equations are written according to the vector potentials. The relations between the induced currents on the conductive patch and the magnetic vector potential which is created by currents that caused at any point in the FSS are expressed by Green's functions. System of linear equations is calculated by applying Method of Moments. These linear equations are solved separately on the CPU and GPU for different sizes of matrix. Scattering and transmission coefficients are calculated from the solution of the linear equations. The current density is calculated by using these coefficients. The electric fields are calculated by current density and the shielding effectiveness of FSS is analyzed. The square type of the patch elements are preferred to the design of FSS for blocking interference and preventing unsuitable waves at 5 frequency band owing to stability of filter response and shielding effectiveness. It is observed that square type of the patch elements give stable results. In addition, CPU and GPU are tested with the solution of systems of linear equations Ax = b separately. GPU time is 0.19 ms and CPU time is 6.22 ms approximately for solution of the A matrix size of 220x220 and b vector size of 220x220. GPU increases the speed of system (approximately 33 times) and provides more effective solutions according to CPU as results.