Browsing by Subject "UHF"
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Item Open Access GaN-on-SiC LNA for UHF and L-Band(IEEE, 2019) Zafar, Salahuddin; Osmanoğlu, Sinan; Çankaya, Büşra; Kashif, A.; Özbay, EkmelIn this paper, we report a broadband GaN HEMT LNA from 100 MHz to 2 GHz, using common source with inductive degeneration and RC feedback topology. Flat gain response of ±1.5 dB variation for 9 V drain voltage with 108 mA drain current bias is achieved. Noise characteristics for frequencies as low as 100 MHz have been explored for the first time for GaN-on-SiC technology. A gain greater than 8 dB with single stage, and promising values of input reflection coefficient (smaller than -8.9 dB) and output reflection coefficient (smaller than -7.1 dB) have been achieved, respectively. Minimum NF of 2.9 dB is achieved while an NF smaller than 5 dB is reported in the usable frequency range from 310 MHz to 2 GHz. Performance evaluation is also done for both low and high drain current and voltage values. In-house 0.15 μm GaN-on-SiC process is used to design this MMIC. The chip size for designed MMIC is 1.35 mm × 1.35 mm.Item Open Access Parasitic effects of the metallic towers on the characteristics of the broadcast antennas(John Wiley and Sons, 2018) Ali, A.; Colantonio, P.; Altintas, A.In this article, we use a tool NEC (Numerical Electromagnetic Code) to model antenna on top of a tower structure. Simulation results for the parasitic effect of the tower on characteristics of broadcast DVB-T (Digital Video Broadcasting Terrestrial) antenna such as input impedance, return loss, gain, front-to-back ratio and radiation patterns are reported. In addition, the effect of a nearby tower on antenna characteristics is studied. A 3D tower and broadband antenna in the UHF (470-862) MHz band are constructed. The antenna works for both digital and analog TV with return loss (RL) ≥ 10 dB, fractional bandwidth of 87% and gain of 12.3 dBi at center frequency. The effective radiated power is calculated by mounting the antenna at each face of the tower to give a satisfactory coverage to a region around the antenna.