Analysis of an H-shaped Patch Antenna by Using the FDTD Method

The characteristics of a small antenna using an H-shaped microstrip patch antenna is analyzed. Significant reduction of antenna size can be realized when the H-shaped patch is used instead of the conventional rectangular microstrip patch antenna. The effect of various antenna parameters like substrate height, radius of shorting post and feed point are analyzed and their effect on return loss is shown.

In this paper, metamaterial superstrate is proposed to enhance the performance parameters of conventional rectangular microstrip patch antenna. The metamaterial is designed using proposed diagonally connected square split ring resonator (DC SSRR). The designed DCS SRR shows the negative values of refractive index for broadband frequency band, 5.0 GHz to 12 GHz. Use of metamaterial superstrate on conventional rectangular microstrip antenna improves the return loss by 18 dB and enhances the gain, bandwidth and radiation efficiency by 1.2 dBi, 28 MHz and 17.5% respectively. The permittivity, permeability and refractive index of metamaterial are numerically computed using MATLAB. All performance parameters of antenna and S-parameters of DC SSRR are obtained using commercially available full wave electromagnetic simulator HFSS based on finite element method and verified by measured results. Good agreement is found between simulated and measured results.

A simple dual-band antenna design and implementation method is proposed in this work, based on the equivalent media properties inspired by resonant metamaterial elements. The equivalent circuit model of dual-band patch antennas based on a complementary split ring resonator (CSRR) is presented and validated. The dual-band patch antenna is designed etching a CSRR in the patch of a conventional rectangular microstrip patch antenna. The first resonance is governed by the quasi-static resonance of the CSRR while the second resonance is originated by the rectangular patch. The fact of etching a CSRR on a rectangular patch antenna also produces a miniaturization of a conventional patch antenna. The equivalent circuit model proposed in this letter is sound in order to understand the functionality of dual-band patch antennas based on a CSRR. Good agreement between simulation, equivalent circuit model and experimental results is shown and discussed. These results lead the equivalent circuit model to become a simple and straightforward tool for the design of this type of multiband antennas, of low cost and versatile operation for a broad range of wireless communication systems.

RFID Tags, typically, require ultra-small antennas and at 900 MHz most of the designs end up being meandered line wire antennas. These may not be suitable because such antennas are heavily influenced by the object on which they are placed. An antenna with a ground plane, such as a microstrip antenna, is a more suitable candidate in that scenario, however, typically micrsotrip patch antennas are large in size. In this paper, we introduce a highly miniaturized microstrip antenna with multiple slots and a superstrate with high-permittivity material. The size of the microstrip antenna at 900MHz is reduced by 87.5% as compared to a conventional rectangular microstrip patch antenna at 900MHz. The gain of the miniaturized antenna is 0.36dBi, achieving 40% efficiency, which is decent enough for short to medium range RFID applications.

In this paper a novel planar antenna is proposed for 5.2GHz band application. The area of designed antenna has been reduced by 52% in comparison to a conventional rectangular microstrip patch antenna. The antenna has three vertical stripes and one horizontal stripe. The length and width of these stripes are varied to tune the antenna for a certain operating frequency. The antenna is fed by using a 50 ohm microstrip line connected at the center of horizontal stripe. The fabricated antenna has return loss of 22dB at 5.27GHz and impedance bandwidth of 120MHz. A parametric study has been carried out to analyze and to find the design sensitive parameters.

This paper presents a novel compact microstrip patch antenna for three-band application, consisting of a main straight arm and four spiral branches. This antenna is characterized by the very small size of only 0.191 /spl lambda/g by 0 212 /spl lambda/g at the first resonance frequency of 5.34 GHz, which represents a size reduction of 60% compared to a conventional rectangular microstrip patch antenna. The results indicate that the return loss is better than 10 dB and that the gain is about 6 dB in each band.

The characteristics of a dual-frequency compact antenna, which uses a rectangular microstrip patch with a shorting pin, are studied. Compared with the conventional rectangular patch antenna, this antenna can achieve both a significant reduction of antenna size and a dual-frequency operation with a single feed. A detailed parameter study is performed. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. The FDTD codes are developed and validated by measurement results. One antenna has been designed and fabricated, and the comparisons between the measured results and the calculated results are provided. The effects of several antenna parameters on two resonant frequencies, frequency ratio, and radiation pattern characteristics of the antenna have been analyzed and compared. The results of the return loss are also presented. It is shown that various frequency ratios (2.82-4.23) can be obtained by varying the design parameters of this antenna. Several design curves are also presented.

A novel dual-frequency compact antenna, which uses an H-shaped microstrip patch loaded with shorting pins, is proposed and studied. This antenna can achieve both a significant reduction of antenna size and a dual-frequency operation with a single feed. More freedom for tuning the resonant frequencies, the ratio of two resonant frequencies, and the input impedance is available due to more design parameters. A detailed parameter study is performed and the theoretical analysis is based on the finite-difference time-domain (FDTD) method. The effects of several antenna parameters on two resonant frequencies, frequency ratio, and radiation pattern characteristics of the antenna are analyzed and compared. It is shown that various frequency ratios (1.91-4.23) can be obtained by varying the design parameters of this antenna. Several design curves are presented.

New version of FDTD with GFM program in Schwarzschild space–time

<span>This paper presents a bandwidth enhancement of a dual-band bi-directional rectangular microstrip patch antenna. The novelty of this work lies in the modification of conventional rectangular microstip patch antenna by using the combination of two techniques: a complementary split ring resonator (CSRR) and a defected patch structure (DPS). The structure of antenna was studied and investigated via computer </span><span>simulation technology (CST). The dimension and position of CSRR on the ground plane was optimized to achieve dual bandwidth and bi-directional radiation pattern characteristics. In addition, the bandwidths were enhanced by defecting suitable shape incorporated in the microstrip patch. A prototype with overall dimension of 70.45×63.73 mm<sup>2</sup> has been fabricated on FR-4 substrate. To verify the proposed design, the impedance bandwidth, gain, and radiation patterns were carried out in measurements. The measured impedance bandwidths were respectively 560 MHz (3.08-3.64 GHz) and 950 GHz (4.64-5.59 GHz) while the measured gains of each bandwidth were respectively 4.28 dBi and 4.63 dBi. The measured radiation patterns were in good agreement with simulated ones. The proposed antenna achieves wide dual bandwidth and bi-directional radiation patterns performances. Consequently, it is a promising candidate for Wi-Fi or 5G communications in specific areas such as tunnel, corridor, or transit and rail.</span>

This paper proposes unique design technique using defected microstrip surface (DMS) for the suppression of higher mode, reduced cross polarization (XP) and improved isolation. The proposed technique can be easily adapted to any conventional working rectangular microstrip patch antennas (RMPA) in the practical applications. The modification can be made by etching the rectangular slots called DMS of optimized dimensions in the rectangular microstrip patch. This will enhance the radiations by suppressing XP radiations and eliminates nearby undesired higher order mode, which is the source for the XP radiations. In this design the conventional RMPA is designed to resonate at 3.04 GHz with broad side radiations with co-polarized peak gain of 5.2dBi and XP of -15.5dB. The proposed RMPA resonates at the same frequency with a gain of 6dBi. The XP is significantly suppressed by 31dB and it is -46.5dB over the span of ±500, with co-pol to cross-pol isolation of 52.5dB is achieved for S-band applications. The performances of the designed antennas have been experimentally verified.

In the present work, the analysis and design of a line fed two-layers coupled rectangular patch antenna is presented. The return loss, the input impedance, and the radiation pattern of the proposed structure are determined using the finite difference time-domain (FDTD) method. The effect of changing the air gap layer thickness between the two layers of that antenna is studied. The results obtained by the FDTD method are found to be in good agreement with the published data. Also it is found that as the air gap layer thickness is increased the 10-dB return loss bandwidth is decreased while the 3-dB beamwidth of that antenna is increased.

This paper presents a novel thin transparent metasurface design which is employed for compensating the out-of-phase radiation from a conventional microstrip patch antenna. Such metasurface mounted on a patch antenna has the ability to transform a primary radiation with spherical-like phase profile into an in-phase planar one. Radiation pattern of the primary source is squeezed into a narrow beam with suppressed side-lobes, thus a patch antenna with enhanced gain performance can be achieved. Due to the strong near-field coupling, the impedance matching bandwidth has been enhanced as well. With operational frequency band set around 5.7 GHz, the proposed antenna has a potential application in wireless communication systems especially for point-to-point data transmission. A prototype of the patch antenna with metasurface superstrate is fabricated and experimentally tested comparing with a conventional patch antenna to validate the simulated analysis, which demonstrates a 3 dB gain enhancement and a doubled impedance bandwidth.

The method of finite-difference time domain was used, and characteristics of the patch antenna based on drilling air holes and embedding a metal boundary in the substrate were studied. The results indicate that the surface waves which propagate along the surface of the substrate can be suppressed by the multiple photonic band-gap structure because of its effect of forbidden band, that it can radiate most of electromagnetic waves' energy in the substrate significantly, and that it has lower return loss (Sll) compared to the conventional patch antennas. Thus, a high gain is attained, its performance is improved. Due to these advantages, the extending use of photonic crystal patch antennas in the areas of mobile communication, satellite communication, aviation, etc., is expected.

With the rapid development of printed circuit technology, printed antennas have found numerous applications in high-performance systems where size, weight, and cost are of significant importance. The most notable feature of these printed antennas is that they are low profile. In particular, microstrip patch antennas and arrays of patches are perhaps the most common form of these printed structures. Extensive investigations into the radiation characteristics of patch antennas began in the 1970s, and both analytical and numerical solutions have been developed for printed antennas. Moreover, the physical insight obtained by these analyses led to the development of several advanced design configurations. While the conventional microstrip patch antenna has a narrow bandwidth, their advanced configurations can achieve broadband and multiband performance. In addition, both circular and linear polarization can be achieved with the patch antenna. In this chapter, we will briefly study some of the fundamentals of microstrip patch antennas, will show the procedure for designing patch antennas using the commercial software package FEKO, and will present several examples.