Circular patch antenna

In today’s world 4G technology has getting lost its existence as 5G enters into the communication world. To develop 5G and its applications 5G antenna design has a major role for developing it. In today’s world there are various types of antenna design but for 5g antenna it can be developed in the form of slot loaded patch antenna design and circular patch antenna design.

Circular cavity is formed which determines the mode supported by the circular patch antenna. Cavity model is used to analyze the patch antenna . Cylindrical perfect magnetic conductor is around the circular periphery of the cavity and two electric conductors at the top represented by patch and the bottom represented by the ground plane forms the cavity. Vector potential is used to determine the field configuration within the cavity.

In this work, a precise and effective approach is applied to calculate important parameters of circular patch an- tenna. Microstrip patch antennas of all shapes are widely used in communication systems where their small size, conformal geometry and low cost can be used to advan- tage. Due to the recent availability of low loss, commer- cial microwave ferrites there is an increasing interest in the performance of the patch antennas printed on ferrite substrates. Although some work [1-6] have been per- formed for microstrip antenna with GA approach for the patch antennas without magnetic biasing but analysis of almost all important parameters for ferrite substrate under magnetic biasing for circular patch antenna is new one. Present analysis also incorporate the dispersion effects due to magnetic field biasing in the form of effective propagation constant (k) which is not discussed in the referenced articles. Some similar referenced works [7-11] also have done mathematically or by conventional me- thods for optimization but this technique is rather precise, accurate and sensitive to optimize parameters of patch antenna as well as other type of antenna also.

Widening bandwidth of a patch antenna has been done in many ways. Typically parasitic patch and L-probe feeding have become the popular techniques for wide-band solutions. An analysis of L-probe-fed technique is described in [2, 3]. A dual-band dual-fed L-probe patch antenna has been reported in [4]. In those papers mainly the L-shaped probe structure and its working principle have been described in detail. Bandwidth increase by parasitic patch has been reported in [5, 6]. Capacitive fed technique, which is used to increase GPS antenna bandwidth, has been described in [7]. L-probe fed circular patch antenna with 30% bandwidth (VSWR ≤ 2) is reported in [8] and has conical shape radiation patterns. Circular patch antenna mode excitation, substrate height, dielectric properties and ground plane effects have been studied in [9]. Some articles [10–13] have reported different patch shapes and patch alteration methods to increase bandwidth. A U-shaped slot wide-band patch antenna with 47% bandwidth (VSWR ≤ 2) and asymmetric radiation patterns in two planes is presented in [10]. However, wide-band radiation properties have not been reported in that article. Multiple U-slots and V-slots for multiple narrow band resonances with L-probe fed antenna are reported in [11]. An L-probe fed H-shaped patch antenna with 22.63% bandwidth at 10 dB return loss is presented in [12]. A direct fed wide-band E-shaped patch antenna design with 30% bandwidth at 10 dB return loss and analysis of multiband E-shaped direct fed patch antenna have been discussed in [13, 14]. The ground plane size effect on antenna properties

Rectangular and circular patch antennas are the most commonly used microstrip patch antennas. Dual characteristics, circular polarization, dual frequency operation, frequency agility, broad band width, feed line flexibility, beam scanning and triple band frequencies can be easily obtained from these patch antennas. Micro strip antennas are widely used in the microwave frequency region because of their simplicity and compatibility with printed circuit technology, making them easy to manufacture. Generally a microstrip antenna or a patch antenna consists of a patch of metal on top of the grounded substrate. The substrate is made of a dielectric material.

A patch antenna is a popular antenna type. The electric field distribution in a rectangular patch is excited in its fundamental mode. The electric field does not stop abruptly at the patch's periphery as in a cavity; Rather, the fields extend the outer periphery to some degree. These field extensions are known as fringing fields and cause the patch to radiate. Some popular analytic modeling techniques for patch antennas are based on this leaky cavity concept. Therefore, the fundamental mode of a rectangular patch is often denoted using cavity theory as the TM10 mode.

This paper presents design andanalysis of probe fed dual U-shape slots antenna. The proposed antenna has simple structure consisting two U-shape slot on a circular patch of radius 13.1mm.The patch is designed on circular shape FR4 substrate material of radius 13.2mm,with height of 5mm and whose permittivity is 4.4.By using only single patch a high impedance bandwidth and dual bands are achieved. Simulated results shows that the return loss is - 24.65dB at the center frequency of exactly 7GHz and the simulated impedance bandwidth (VSWR<2) is 24% .The antenna is designed and simulated using HFSS software and theoretical results gives good agreement with simulated results. Return loss, 3D gain, radiation pattern are simulated for the proposed designed antenna was presented.

4.20 Gain and directivity circular slot patch antenna 44 4.21 Surface current circular slot patch antenna 44 4.22 Radiation pattern circular slot patch antenna 44 4.23 Radiation pattern of circular patch antenna 45 4.24 Return loss circular patch slot double layer 49 4.25 Gain and directivity circular patch slot double layer 49 4.26 Surface current circular patch slot double layer 50 4.27 Radiation pattern circular patch slot double layer 50 4.28 Radiation pattern of circular patch antenna 51 4.29 X-circular polarize microstrip patch antenna configuration 51 4.30 Return loss X-Circular Polarize Microstrip Patch Antenna 53 4.31 Radiation pattern X-Circular Polarize Microstrip Patch Antenna 54 4.32 Gain and directivity X-Circular Polarize Microstrip Patch Antenna 54 4.33 Surface current X-Circular Polarize Microstrip Patch Antenna 54 4.34 Radiation pattern of X-Circular Polarize Microstrip Patch Antenna 55

Various methods for single-feed circularly polarized microstrip antennas have been published in the literature. A method has been proposed to make circularly polarized radiation for a square patch using the truncated- corners method and a rectangular slot embedded at the square patch’s center [2]. However, the truncated-corners method did not provide any size reduction and parametric study has not been considered regarding bandwidth. Later, established a single-feed circularly polarized technique using a cross slot embedded at the center of the circular patch [3]. The antenna structure was based on a proximity feed. A coaxially fed cross-slot circular patch antenna was also proposed [4]. The circularly polarized radiation could be achieved with a circular microstrip-patch antenna by using a tuning stub [5]. However, the tuning-stub method is expensive to manufacture and also was not useful for a compact circularly polarized microstrip-antenna design. The circular-ring microstrip antenna with two symmetrical inner stubs can also be used for circular polarization [6]. Recently, single feed circular patch antenna with circular polarization was proposed by embedding circular holes in microstrip resonator [13]. Simply embedding two circular slots can stimulate two orthogonal near-degenerate modes. With proper size and position of two slots on circular patch, single band and dual band CP operation can be generated separately. Good impedance matching and axial ratio for both single band and impedance matching for dual band operation are achieved, but bandwidth and radiation pattern obtained was poor [7].

Circular microstrip antenna (CMSA) with circular polarization has many applications. CMSAs are compact in size which suits the requirements of device miniaturization [1-3]. This work uses coaxial feeding mechanism for the proposed antennas. Coaxial feeding enables compact structure [3] and also facilitates in generating circular polarization [4]; as coaxial feeding mechanism does not disturb the symmetry of the structure. Symmetrical structure of CMSA makes it suitable choice for creating an antenna with circular polarization capability. Circular polarization is generated through CMSAs by introducing small asymmetry as a result of mathematical/simulation driven design changes, in the otherwise symmetrical structure. Circular polarization antennas eliminate the orientation settings requirement which otherwise are essential in case of linear polarization antennas. Generation of circular polarization by modifying ordinary circular patch antenna has two major design aspects to be taken care of: (1) gain (2) circular polarization bandwidth (axial ratio bandwidth). As the modification generally means cutting slots from the patch; which certainly degrades gain performance. So care must be taken to cut very small slots optimum for the purpose so as not to degrade the gain performance considerably and at the same time it must be solving the purpose of generating circular polarization. Unlike return loss (impedance) bandwidth axial ratio (circular polarization) bandwidth values are smaller. So maximizing axial ratio is a big design concern for microstrip antenna with circular polarization characteristics. Bandwidth enhancement can be achieved either by increasing the thickness of the substrate or by reducing the dielectric constant of the substrate. In literature [6-15] various circular patch antennas have been proposed. Many of these have proposed the trade-offs between dielectric constant and other parameters.

Circular patch antenna is a popular patch antenna used for various purposes in modern technology. Itis used not only the single element but also in array form and it is analyzed by treating the patch, ground plane and the material between the two as a circular cavity.[2]

This paper presents a study about Microstrip Circular patch antenna for S band satellite application. We proposed it for Indian Regional Satellite System which having the operational frequency band of 2-4 GHz. The DGS (Defective Ground Structure) implies a defective ground structure in place of a simple conventional ground structure. The developed design is succeed to achieve a low profile return loss. We simulate the prototype on HFSS with Rogers RT duroid and FR4 Epoxy materials. The proposed antenna achieved the bandwidth of 166.2 MHz The proposed prototype is consisting of two frequency bands for operation with low profile S parameters.

The circular patch antenna [1] is designed by using the following formulas (5) to (8) [6]. The outputs can be controlled by varying the effective radius of a circular patch antenna. Fig. 2 shows the circular patch antenna with proximity feeding.

In our experiment we found that Probe-fed Rectangular patch antenna had a marginally better performance than that of the Probe-fed circular patch antenna. The best performance that we are able to obtain practically is a return loss of 25.73dB and a VSWR ratio of 1.22 : 1 in the Probe-Fed Rectangular patch antenna. Proper Impedance matching is the key to obtaining lower return loss and higher gain. The voltage standing wave ratio is a measure of how well a load is impedance-matched to a source. The Antenna Gain also depends on the amount of conductor and dielectric losses in the Microstrip antenna.

In January 23, 2014, Liu et al. proposed a monopolar circular patch antenna loaded with shorting vias and a coupled annular ring in [14] to achieve a wider bandwidth by coupling three modes. The antenna achieves a bandwidth of 27.4% with a very low profile and has an omnidirectional pattern like a monopole antenna.

This paper presents the simulated results of a compact varactor diode integrated conventional circular patch antenna and also compares the results with a similar patch antenna. Proposed microstrip patch antenna (MSA) was designed and simulated using HFSS.V.13 and CST MWS and its various parameters such as return loss, VSWR and input impedance were determined, and shape of this MSA was modified by cutting various slots in it at appropriate positions. The diode is modeled as a switch for the frequency band from 2.85 to 3.0 GHz. The proposed antenna also gives CP radiation with slots. In addition to it is observed that the proposed antenna shows frequency agility behavior in the frequency ranges 2.85 to 3.0 GHz with bias voltage varying from 0 to 5V or in ON and OFF state. A bandwidth enhancement and miniaturization is also achieved.

This paper presents a reflector array which is designed at mm band (79GHz) for the applications like, it is easy to achieve gigabit rates with the help of mill metric wave technologies and it includes video transmission from set-top-box (STB) to an HDTV. Here the reflector array is considered as receiving antenna and the transmitting antenna is taken as microstrip patch antenna, the circular patch antenna, patch antenna and patch antenna with a coaxial feed. The simulations were done by using An-soft HFSSv13. The simulated array antenna is designed by using Rogers ultralam 1300 with dielectric constant 3mm.

Circular patch micro strip antennas are the light weight, low cost, low volume and easily manufacturable antennas and becoming progressively popular due to their additional advantages of its compatibility with microwave, millimeter integrated circuits (MIC's) and monolithic microwave integrated circuits (MMIC's) because of this reason they are also capable of producing Circular polarization which finds application in airborne and spacecraft application. Changing the design of Circular patch microstrip antenna with respect to its radius, slots and feeding techniques as our motive was to achieve miniature antenna with better results in terms of return loss and bandwidth and impedance matching than conventional antenna’s. The solution provided by IE3d which is method-of- moments-based electromagnetic (EM) software. It is analytical and therefore more methodical and accurate than numerical and ray tracing techniques. This paper reviews the performance analysis of A circular patch antenna which provides linear polarization and monopole-like radiation pattern [2016], Circular Array Patch Antenna of 2 × 1 array dimensions with Double Circular Slots [2015], Annular-Ring Slot Antenna for WiMAX and WLAN Applications and giving Circularly Polarization [2014] and Microstrip Antenna of Narrow Half-Ring and Half- Circular Patch giving Dual-Frequency band [2013].

ABSTRACT: In this paper a circular microstrip patch antenna with embedded circular slots to obtain harmonic suppression and peripheral cuts for producing circular polarization (CP) is proposed and analyzed. Antenna is designed by taking into consideration the use of Active Integrated Antennas [1] and rectifying antennas (rectenna) [2]. Low cost FR4 epoxy is used as the substrate and 2.45GHz/802.11a as the design frequency. Simulated 10dB return loss bandwidth of 171MHz and CP 3dB axial ratio bandwidth of 46MHz is obtained. Size reduction of 4% is also obtained as compared to the conventional circular patch antenna with linear polarization (LP). Simulations and optimizations are performed by using High Frequency Structure Simulator (HFSS) software.

346 | P a g e In this paper, we present an inset-fed modified circular microstrip patch antenna by inserting an omega type slot at the centre and arcs at the edges of circular patch. The proposed antenna resonates at six different frequencies covering different wireless communication bands. The details of the antenna design, simulation and experimental results are presented and discussed in next sections.