The partial charge simulation method is presented to solve the characteristicimpedance of the transmission line of specific cross section with an offset inner conductor.Thismethod has a higher accuracy due to the accu...The partial charge simulation method is presented to solve the characteristicimpedance of the transmission line of specific cross section with an offset inner conductor.Thismethod has a higher accuracy due to the accurate satisfaction of the boundary condition on theouter conductor.The combined method of the Gauss elimination and optimization is used tosolve the equation of charge simulation,and it is an effective method for increasing the accuracyand assuring the convergence.The Green’s functions of five transmission lines(i.e,with circular,elliptic,rectangular,trough and slab conductor)are given.展开更多
Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. A...Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. Astronomy is not left out;as a study of everything beyond earth’s atmosphere, useful signals have to travel great distances to reach us. Hence the need for equipment to detect such signals. The Helical Antenna is known to possess high gain (directivity) and can process signals with any type of orientation/polarization which implies high sensitivity hence the desire to use it. Simulation was done using the legacy 4NEC2 software. The purpose of this paper is to design a circularly polarized helical antenna operating in axial mode that is suitable for detection of neutral hydrogen line emission at the frequency of 1420 MHz and to show how it can be used as a feed for an off-set parabolic dish.展开更多
文摘The partial charge simulation method is presented to solve the characteristicimpedance of the transmission line of specific cross section with an offset inner conductor.Thismethod has a higher accuracy due to the accurate satisfaction of the boundary condition on theouter conductor.The combined method of the Gauss elimination and optimization is used tosolve the equation of charge simulation,and it is an effective method for increasing the accuracyand assuring the convergence.The Green’s functions of five transmission lines(i.e,with circular,elliptic,rectangular,trough and slab conductor)are given.
文摘Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. Astronomy is not left out;as a study of everything beyond earth’s atmosphere, useful signals have to travel great distances to reach us. Hence the need for equipment to detect such signals. The Helical Antenna is known to possess high gain (directivity) and can process signals with any type of orientation/polarization which implies high sensitivity hence the desire to use it. Simulation was done using the legacy 4NEC2 software. The purpose of this paper is to design a circularly polarized helical antenna operating in axial mode that is suitable for detection of neutral hydrogen line emission at the frequency of 1420 MHz and to show how it can be used as a feed for an off-set parabolic dish.
