ABSTRACT: In this paper, the design and implementation of a co-axial feed U-slot microstrip antenna for 5.5 GHz WLAN application is presented. The VSWR (Voltage Standing Wave Ratio) and the return loss of this proposed structure are studied and analyzed using Computer Simulation Technology (CST) microwave studio, it’s based on the method of finite difference time domain techniques to achieve the desired specification. The proposed antenna based on co-axial feed configuration has the maximum achievable bandwidth obtained about 260 MHz (5.36-5.62 GHz) at -10db reflection coefficient which corresponds to WLAN 5.5 GHz frequency band and maximum achievable gain is 5.3db at 5.5 GHz centre frequency. The stable VSWR and low return loss are obtained across the frequency band compared to the existing system.
Abstract—A broadband stacked U-slot microstrip patch antenna is presented using circuit theory concept. The antenna shows two resonance frequencies that are very closely spaced to give broadband characteristics. The frequency band of 186 MHz (36.4% impedance bandwidth) is achieved for the proposed antenna. The theoretical results are in good agreement with the simulated results.
ABSTRACT: A multiband U-slot patch antenna, with linear polarization, is designed for WiMAX and WLAN systems. The impedance bandwidths (dB) of 2.3%, 3.4%, 7.2% and 5.2% were achieved at central frequencies 3.3 GHz, 3.7 GHz, 5.3 GHz and 5.8 GHz, with gains of 5 dBi, 7.3 dBi, 7.5 dBi and 8.2 dBi, respectively. The antenna is designed with coaxial feeding technique and the overall dimension is around 50X50 on FR4 substrate. The simulation results of reflection coefficient, gain, radiation patterns and field distributions are carried and presented in this work with FEM based electromagnetic tool HFSS.
Having a critical look at the available literature it can be concluded that the use of frequency reconﬁgurable antennas dramatically reduces the overall system overheads [4–10]. In frequency reconﬁgurable slot antenna, frequency tuning is done by scaling the antenna dimensions electrically, by the integration of micro-electro-mechanical systems (MEMS) switches , PIN diodes [9, 10], varactor diodes , etc. Majid et al.  presented a switchable slot in the antenna ground plane for realizing nine frequency switching from 1.98 GHz to 3.59 GHz using 5 PIN diodes. In , a frequency and pattern reconﬁgurable microstrip slot antenna is reported. In , a pixel slot antenna which can reconﬁgure its resonating frequency in six diﬀerent bands ranging from 2.2 GHz to 4.75 GHz using ﬁve PIN diode is reported. In , unequal U-slot antenna loaded with two varactors for 6 diﬀerent frequencies switching between 2.3 GHz and 3.6 GHz is reported. These reported methods for achieving frequency reconﬁgurability require complex biasing circuits leading to an increased complexity of overall structure.
The aim of the project is to design u-slot rectangular microstrip Patch antenna and to study their radiation pattern, return loss, VSWR, gain and directivity. Length and Width of the antenna can be predicted using the design equation. Microstrip antenna is simulated by Ansoft HFSS software which has its operating frequency range (5.18-5.8)GHz. As in modern communication is concerned in size reduction and portability, miniaturization and good cost to quality ratio are the main things in our project.
Abstract: A wide band dual-beam micro strip antenna is proposed in this communication. Two radiation beams off broadside are obtained by Operating the patch antenna at the higher order mode instead of the Fundamental mode, this radiates a broadside beam. Broadening the antenna bandwidth is achieved by using the U-slot technique. Unlike previous work on the conventional U-slot micro-strip antenna, the effect of the U-slot inclusion on the performance of a patch antenna operating at the mode is studied across the entire achieved bandwidth. The antenna analysis is carried out with the aid of full wave simulation, and an antenna prototype is fabricated and measured for validation. Good agreements between the simulated and measured results are observed. The antenna operating frequency range is 5.18–5.8 GHz with VSWR less than 2, which corresponds to 11.5% impedance bandwidth. It exhibits two radiation beams, directed at 35% and % with 7.92 dBi and 5.94 dBi realized gain, respectively at 5.5 GHz.
The U-slot rectangular patch antenna made of the dielectric constant of 2.33, and it works on a three-dimensional EDTD method to measure the performance of the antenna. It increases the quality factor. The maximum bandwidth was twenty-five percent, and the calculated gain is 6.5dB. Hence there are various methods applied to boost up the gain of U- slot rectangular microstrip patch antenna to the frequency. So in this proposed method, the gain is increased in the frequency of 1.157 GHz by placing an array of microstrip antennas.
In this paper we present a novel approach to improve the bandwidth of Microstrip patch antenna using thick substrate and by inserting Uslot and H slot in the Truncated rectangular microstrip antenna. By inserting only H slot in the Truncated rectangular microstrip antenna the impedance bandwidth was 21.2% whereas after adding Uslot in same design the bandwidth is increase up to 50.7% in the frequency range 1.5 GHz to 2.67 GHz. The Uslot is used to tune impedance matching. The radiation pattern has acceptable response at both E and H plane. The antenna is designed at glass epoxy substrate with dielectric constant 4.4, fed by a coaxial feeding technique. Detail of the proposed antenna and the simulated results are presented.
Abstract—In this paper, an asymmetric U-slot patch antenna with low probe diameter is presented. It will be shown that reduction in probe diameter causes in reduction in bandwidth. One of the characteristics of this antenna is keeping the bandwidth in 30% in spite of reduction in antenna size and use of low probe diameter compared to antenna presented in . The presented antenna in this paper has been fabricated by pcb technique and tested. The far-ﬁeld results have also been presented based on simulation and measurement. Although the antenna has high cross polarisation level, in the case of using circular polarisation, the use of this antenna can be recommended because of its reduced size, high impedance bandwidth, high total gain in spite of having low size, and ease of fabrication.
Fig.2 (a) is the proposed rectangular single-patch antenna with U-slot structure that is calculated and optimized using patch antenna equations . Fig.2 (b) and (c) present the assigned boundary to ground plane and patch respectively. Fig. 4 (c) present radiation for air box to model free space radiation. A radiation boundary is used to emulate free space by truncating infinite free space to finite calculation domain. This minimize reflections from outer surfaces and ensures maximum absorption.
ABSTRACT: In this paper, two different slot antennas have been simulated using HFSS software. A basic slot antenna is compared with a Uslot antenna. This is done by increasing the number of slots in basic slot antenna. Both the antennas hold their applications in satellite communication. Rogers RT/duriod 5880 substrate is used as dielectric material for the simulation setup. In this research work, we have comparatively evaluated various parameters like return loss, radiation pattern, gain, voltage standing wave ratio (VSWR) and directivity for slot and U-slot antenna.
From the detailed study, it is found that the CRMSA can be made to operate at different bands between 3 to 12 GHz by loading U and inverted U-slot on the radiating patch. The insertion of U and inverted U-slots also enhances the gain from 0.90 to 1.73 dB. The multi bands of CTUAIURMSA gives almost constant frequency ratio, and the resonating bands can be tuned on either side of the frequency spectrum by changing the width of horizontal and vertical arms of U and inverted U-slot without affecting the primary band. Tuning of multibands does not affect the nature of broadside radiation characteristics. The proposed antennas are simple in their geometry and fabricated using low cost glass epoxy substrate material. These antennas may find applications in WiMax (3.4 to 3.6 GHz), WiMax of IEEE802.16d (5.7–5.9 GHz), HIPERLAN/2 (5.725 to 5.825 GHz) and radar communication systems.
ABSTRACT: In this paper, a dual frequency resonance antenna is analysed by introducing U-shaped slot in a rectangular patch, the results in terms of return loss and radiation pattern are given. It is observed that various antenna parameters are obtained as a function of frequency for different value of slot length and width; it is easy to adjust the upper and the lower band by varying these different antenna parameters. In the present work variation of substrate permittivity is also studied. All the theoretical results using Matlab are compared with the simulated results obtained from Ansoft HFSS which are in close agreement.
The proposed antenna explains and illustrates the simulation of the microstrip antenna with single u-shaped slot on the patch. This antenna is compact, have a flexible structure and easy to use compared with other antennas. Thus, the very low return loss of less than -12dB is achieved which is suitable for the wireless applications and in the c-band of satellite communication systems. This antenna has been simulated for the frequency of 5.5GHz and is well known for its wideband characteristics.
In this paper, a compact microstrip-fed slot antenna with triple- band operation is presented for wireless communication systems. The antenna is constructed by etching multiple open-ended slots in the ground plane, including inverted U-slot, inverted L-slot and reversed F-slot, which is excited by a cross-shaped microstrip feed line shorted to the ground on the other side of substrate. These design skills are introduced to approach excitation of triple resonant modes accompanied with stable radiation characteristics over the operating bands. The design method and result discussions are provided in the following.
Broadband microstrip antenna is more commonly realized by cutting slot inside the patch. While designing slot cut antennas at a given frequency, slot length is taken to be either quarter wave or half wave in length. However this simpler approximation does not give closer result. In this paper, an analysis to study the effect of slot like, half U-slot and rectangular slot on the broadband response of Semi-circular microstrip antenna is presented. It was observed that the slot does not introduce any additional mode but reduces the resonance frequency of second order TM 21 mode of the patch
From the simulation result we can see that the antenna resonate in three bands. This antenna can be used for many applications but after adding U-slot in basic configuration reflection coefficient of antenna enhances up to greater extent as seen in the modified geometry.