#THE FRONT VIEW OF CST MICROWAVE STUDIO TV#

In this way, each dipole operates in resonance condition at a certain frequency and this happens when the dipole length L is equal to half wavelength (О»/2). The LPDA is designed by using several dipoles of different lengths. A very useful design procedure of LPDA has been proposed by Carrel. Each dipole of LPDA is connected to the feeding source, whereas in Yagi-Uda antenna only one dipole is connected to the feeding source and all other dipoles are passive. Furthermore, the most important difference between the two antennas lies in their feeding patterns. However, the LPDA has much larger bandwidth compared to Yagi-Uda antenna. LPDAs provide better front-to-back ratio but relatively lower gain than Yagi-Uda array antenna. The gain of the antenna can be increased by increasing the number of dipoles. Log-periodic dipole arrays (LPDAs) present an almost flat gain over a wide operating bandwidth.

#THE FRONT VIEW OF CST MICROWAVE STUDIO TV#

Log-periodic antennas are widely used because of their broadband characteristics in TV reception, electromagnetic compatibility measurements and wideband precision measurements. The Trusted Region Framework algorithm seems to have the best performance in adequately optimizing all predefined goals specified for the antenna. The optimization process has been implemented by using various algorithms included in CST Microwave Studio, such as Trusted Region Framework, Nelder Mead Simplex algorithm, Classic Powell and Covariance Matrix Adaptation Evolutionary Strategy. The antenna is then optimized to concurrently improve voltage standing wave ratio, realized gain and front-to-back ratio. The practically measured realized gain is in good agreement with the simulated realized gain. The comparison between these simulations is presented to ensure accurate modelling of the antenna. Two simulations of the antenna are initially performed in time and frequency domain respectively. In this study, a log-periodic dipole array is measured, simulated, and then optimized in the 470вЂ“860В MHz frequency band.

Such antennas are extensively used in electromagnetic compatibility measurements, spectrum monitoring and TV reception.

Log-periodic antenna is a special antenna type utilized with great success in many broadband applications due to its ability to achieve nearly constant gain over a wide frequency range.

The front view of cst microwave studio