Osama Ahmed

A Printed Monopole Antenna With Two Steps and a Circular Slot for UWB Applications

This letter presents a printed monopole antenna with two steps and a circular slot for ultrawide band (UWB) applications. The proposed antenna is fabricated and tested. The proposed antenna has a wide frequency bandwidth of 8.4 GHz starting from 3 GHz up to 11.4 GHz for a return loss (S_11) of less than - 10dB and gain flatness over the frequency range. Measured results show also that the proposed antenna features satisfactory radiation characteristics within the achieved impedance bandwidth. By introducing a simple and proper narrow slot in the radiating element, frequency-notched characteristics can be obtained and a good band-notched performance in the 56 GHz band can be achieved.

A NOVEL MAPLE-LEAF SHAPED UWB ANTENNA WITH A 5.0{6.0 GHz BAND-NOTCH CHARACTERISTIC

A novel microstrip fed ultra-wideband (UWB) antenna with difierent band rejection techniques is presented in this paper. The antenna consists of a maple-leaf shaped radiator fed by a microstrip line with a flnite ground plane on the other side of the substrate. The size of the UWB antenna is 30:5£35:5mm 2 which is only about 0:3£0:35‚ 2 at 3GHz. The calculated impedance bandwidth of the proposed antenna ranges from 3GHz to 14GHz with relatively stable radiation patterns. Two difierent techniques have been implemented to achieve band-notch characteristic in the 5.0{6.0GHz WLAN frequency band. The flrst one uses an H-shaped slot cut away from the radiating patch while the other one uses two rectangular slits in the ground plane creating defected ground structure (DGS).

A modified Wilkinson power divider/combiner for ultrawideband communications

A modified Wilkinson power divider/combiner using one added stepped-impedance open-circuited radial stub on each branch is proposed for UWB applications. The stepped-impedance open stub is used to introduce multiple transmission poles through the whole UWB frequency spectrum. The simulation results of the proposed small size and low cost power divider have shown equal power split between the two output ports with good insertion loss and satisfactory isolation within the whole UWB frequency range. Also, it has been shown that the designed UWB power divider has good return loss of all ports.

Size Reduction and Bandwidth Enhancement of a UWB Hybrid Dielectric Resonator Antenna for Short-Range Wireless Communications

In this paper, a novel hybrid dielectric resonator (DR) antenna for Ultrawideband (UWB) short-range wireless communications is proposed. The proposed antenna consists of a microstrip fed monopole loaded with a half cylindrical dielectric resonator antenna of Rogers RO3010 mounted on RT5880 substrate with a flnite ground plane. The microstrip line fed monopole antenna is on the other side of the substrate. Compared to the conventional circular cylindrical DR mounted on a flnite ground plane (reference antenna), the proposed antenna has a reduction in the antenna size by about 30% with a bandwidth increase by about 22% than the reference antenna. The proposed antenna has a good impedance bandwidth. In addition, the proposed antenna has a quite higher and more stable gain than that of reference antenna. Moreover, the antenna has a good omni-directional radiation patterns in the H-plane. The proposed antenna is considered a good candidate for UWB short-range wireless communication systems.

A compact UWB butterfly shaped planar monopole antenna with bandstop characteristic

In this paper, a novel compact butterfly shaped planar monopole ultra-wideband (UWB) antenna is presented. This antenna is proposed and designed with a standard printed circuit board (PCB) process for suitable integration with MMICs and other components. The calculated impedance bandwidth of the proposed antenna ranges from 3GHz to 12GHz for a return loss S11 less than -10dB. Also, it has a relatively stable radiation patterns over its whole frequency band of interest. By introducing a slit ring resonator (SRR) in the feedline, a bandstop of 830MHz (from 5.0 to 5.83GHz) for band rejection of WLAN can be achieved. So, the proposed antenna is considered a good candidate for UWB applications.

Mutual Coupling Effect on Ultrawideband Linear Antenna Array Performance

This paper studies the mutual coupling effect between array elements of two- and four-element ultrawideband (UWB) linear arrays on their performances. For simplicity, it is assumed that both antenna arrays are fed by independent microstrip lines with the same power amplitudes and equal phases. From our study, array bandwidth improvement is achieved for both array types when the mutual coupling is strong enough or interelement spacing is small. The mutual coupling also enhances the array realized gain especially in the midfrequency band (5–8.5 GHz) while it deteriorates the gain outside that frequency range. Proper tuning for interelement spacing with enough mutual coupling enhances the array realized gain at most frequencies and makes it more stable across the desired frequency range. From the radiation pattern results, the grating lobes appear in UWB arrays when the element spacing is greater than two wavelengths at the upper edge frequency, 10.6 GHz, or half wavelength at the lower edge frequency 3.1 GHz. Two fabricated array prototypes with corporate feed are fabricated and tested to validate the theoretical analysis. The effect of using T-junction power divider is clear on the reflection coefficient |S11|. Both numerically simulated and experimental results successfully demonstrate our analysis.

STUDY OF ELLPITICAL SLOT UWB ANTENNAS WITH A 5.0{6.0 GHz BAND-NOTCH CAPABILITY

Two microstrip fed ultra-wideband (UWB) antennas with difierent band rejection techniques are presented in this paper. The designed antennas consist of a defected ground plane with an elliptical slot and two difierent radiator shapes. The flrst design is composed of a half circular ring radiator element while the second one uses a crescent shaped radiator. The radiators are fed by a 50› microstrip line with a tapered microstrip transition to ensure good impedance matching. The calculated impedance bandwidth of the proposed antenna ranges from 3GHz to 14GHz with relatively stable radiation patterns. To achieve band-notch characteristic in the 5.0{6.0GHz WLAN frequency band, two difierent techniques have been implemented. The flrst technique uses a C-shaped slot etched in the ground plane while the other one uses another C-shaped slot in the feed line.

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF A NOVEL ULTRAWIDEBAND BUTTERFLY SHAPED PRINTED MONOPOLE ANTENNA WITH BANDSTOP FUNCTION

In this paper, a novel compact butter∞y shaped printed monopole antenna for ultra-wideband (UWB) applications is presented. The proposed antenna is designed with a standard printed circuit board (PCB) process for suitable integration with other microwave components. The antenna prototype is designed then fabricated and tested experimentally. The calculated impedance bandwidth of the proposed antenna ranges from 3GHz to 13GHz for a 10dB re∞ection coe-cient (S11) while the measured impedance bandwidth ranges from 3GHz to 10.8GHz covering the whole UWB frequency range. The measured antenna radiation patterns show relatively stable radiation patterns with almost constant gain over the whole frequency band of interest. By introducing a slit ring resonator (SRR) in the feedline, a bandstop of 830MHz from 5.0 to 5.83GHz for band rejection of wireless local area network (WLAN) can be achieved. So, the proposed antenna is considered a good candidate for future UWB communication systems.

Study a compact printed monopole antenna with two notches and an offset circular slot for UWB communications

In this paper, we presented a compact monopole antenna for UWB communications. It has been demonstrated that the proposed antenna can yield an UWB bandwidth of return loss less than -10 dB, from 3 GHz to 11.4 GHz covering the frequency band for most UWB communication systems. It is also observed that the proposed antenna exhibits a reasonable omni-directional radiation patterns in the H-plane. The proposed antenna can be a good candidate for future UWB systems. Further simulation and measurement results will be presented and discussed during the conference sessions.

Electromagnetically-Coupled Millimeter-Wave Antenna Array with Non-Uniform Distribution for 60 GHz ISM Applications

Abstract—In this article, the design of an electromagnetically-coupled millimeter-wave elliptical patch array antenna prepared to work in the 56–65 GHz (14.8%) frequency band is presented. The introduced antenna array is designed for low-loss, high-gain and low cross-polarization levels. The proposed antenna exhibits a measured gain of 8 dBi and good linear polarization across the desired frequency range. It has a good side lobe suppression better than 17 dB in both Eand H-planes. Measured and simulated results confirm that this antenna is a good candidate for short-range wireless communication applications at millimeter-wave frequencies.