Effective Parameters of Low Frequency Antennas

investigation of effective parameters on the rigidity of light composite diaphragms (psscb) by fem

در این رساله با معرفی سقف های psscb متشکل از ترکیب ورق های فولادی ذوزنقه ای و تخته های سیمانی الیافی به عنوان سقف های پیش ساخته (سازگار با سیستم سازه ای قاب های فولادی سبک) به بررسی پارامترهای موثر بر صلبیت سقف، پرداخته می شود. در تحقیق حاضر ابتدا به مدل سازی دو نمونه سقف آزمایش شده، به روش اجزاء محدود با استفاده از نرم افزار تحلیلی abaqus ver 6.10 پرداخته شده است. نمونه های ساخته شده تحت اعما...

Beam Patterns of Low Frequency Radio Antennas using LEO Satellites

Low-loss tuning circuits for frequency-tunable small resonant antennas

Minimization of power loss in the tuning circuits of frequency-tunable small resonant antennas, such as microstrip patches, is studied. First, the frequency shift and the associated power loss in certain tuning circuits are theoretically calculated based on approximate circuit models of fairly narrow-band resonant antennas. By investigating the ratio of frequency shift and loss, an optimal conf...

OLFAR - Orbiting Low Frequency Antennas for Radio astronomy

New interesting astronomical science drivers for very low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high energy cosmic rays. Huge efforts are currently made to establish low frequency Earthbound instruments, since today’s technology is able to support this. However, astronomical observations with E...

Dual-Frequency Patch Antennas

Dual-hequency patch antennas may provide an alternative to large-bandwidth planar antennas, in applications in which large bandwidth is really needed for operating at two separate transmitreceive bands. When the two operating frequencies are far apart, a dual-frequency patch structure can be conceived to avoid the use of separate antennas. In this paper, a critical overview of possible solution...