جستجوی مقالات مرتبط با کلیدواژه « monopole antenna » در نشریات گروه « برق »

In this article, a compact ultra-wideband monopole antenna with notch band characteristic is presented. The proposed antenna has a notch-band for rejection of WiMAX frequency at 3.5GHz. Here, we show the ability of controlling the notch frequency with some changes in U-slot. The antenna has the bandwidth of 3.1-16 GHz with the notch at 3.2-3.8GHz with high rejection and VSWR of notch around 16. The prototype antenna based on monopole antenna with dual U-shape slots is fabricated. The antenna ground contains a T slot for matching. The antenna has Omni-directional pattern in E-plane and bi-directional pattern in H-plane. The antenna gain has altered from -8 to 5.9 dB at the range of 2–16 GHz, with an average gain of 4.2 dBi. The total size of the antenna is 12×18×1.6 mm3. The multi U line controls the current distribution, while it can be replaced by pin diode for achieving reconfigurable structure.

In this paper, a planar monopole antenna is introduced, also we added some new Nano fillers such as Fumed Silica and Aluminum Oxide to RT Duriod5880 and RO3003 to produce new Nano composite materials, then new Nano composite materials are used as a substrate of a ultra-wideband monopole antenna. Antenna characteristics are considered to illustrate that, by using these Nano composite materials, antenna bandwidth has significantly improved. The return loss and radiation pattern plots of the simulated planar monopole antenna show good results. Another advantage of this modification is simple fabrication and narrow substrate thickness of the proposed monopole antenna.

It is known that if a conductor resides in the neighboring of an antenna with a small distance relative to the wavelength, it induces a reverse current on the conductor. This paper involves the unavoidable coupling effects on some common types of LF antennas, due to the large wavelength in this frequency band. In particular, after some discussions about top-loaded antennas, the coupling effect of wire supports is studied for these antennas. In addition, the effect of support masts on the radiation resistance is shown for three kinds of Loran transmitter antennas with four masts. Furthermore, some formulas for the impedance of small monopole antennas with neighboring masts are proposed and some simulation results of practical antennas are reported. Finally it is indicated that the coupling effect is more destructive for sectional Loran transmitter antenna compared with square top loaded antenna.

This paper presents the results of a new monopole antenna that exhibits 2.75-10.7 GHz performance. The proposed antenna consists of a radiating patch with notches excited by capacitive coupling feed. Also, the antenna’s truncated ground-plane incorporates a central notch. This modification significantly improves the antenna’s impedance bandwidth by 118% over an ultra-wideband frequency range. These characteristics make the proposed antenna an excellent candidate for numerous UWB applications and next generation communication systems. The key physical parameters affecting the antenna’s frequency characteristics have also been investigated in order to determine optimum antenna performance. The antenna’s simulated return-loss, and E-plane and H-plane radiation patterns show very good correlation with the requirements of UWB applications.