Design and Analysis of Patch Antenna for C, X, Ku Band Applications

This paper presents the design and simulation of patch antenna loaded with metamaterial called Complementary Split Ring Resonator (CSRR) with increased gain and bandwidth suitable for wireless applications such as satellite, TV and radar applications. FR4 substrate with dielectric constant (ε r ) of 4.4 is used. The radiating patch consists of CSRR structure fed by microstrip line to achieve triple(C, X, K u ) band characteristics. The proposed antenna is designed and simulated using Ansys High Frequency Structural Simulator (HFSS). The proposed antenna with 4 rings having a resonant frequency of 7.662, 9.8510, 10.9455, 11.8410, 12.7365 and 13.7315GHz and the bandwidth of 230, 1090, 640, 580, 620 and 2000MHz respectively. The proposed antenna with 6 rings also having a resonant frequency of 7.7615, 9.9525, 11.0450, 11.9405 and 13.7315GHz and bandwidth of 160, 1130, 490, 1360 and 1480MHz are achieved. The proposed antenna is analyzed in terms of return loss, VSWR, gain and bandwidth. The electric field and surface current distribution were observed for the proposed antenna having 6 rings. terrestrial

operates in a bandwidth ranges from 2.59 to 3.26 GHz, 9.39 to 10.12GHz, 10.6 to 12.2 GHz and 12.3 to 12.8GHz. The above resonant frequencies were located at S, X, Ku bands.
The coupled ring split ring resonator is designed for microwave applications. The antenna is fabricated using FR4 substrate. The antenna operates in a bandwidth ranges from 2.15 to 2.3GHz, 4.45 to 4.95GHz, 5.7-6.1GHz and 8.46 to 9.2GHz. The proposed metamaterial structure is suitable for S, C, X band applications [6]. The symmetrical meandered monopole radiators and Y shaped element. The split ring resonator is used to reduce the interference signal coupled to the antenna system which in turn reduces the mutual coupling effect. The proposed MIMO antenna having bandwidth ranges from 3.3 to 3.6 GHz and 4.8 to 5 GHz and after the addition of split ring resonator the experimental results showing that the mutual coupling between the two elements is below -25dB in the operating band [7].
The microstrip rectangular patch antenna is loaded with complementary split ring resonator was designed. The proposed antenna operates in three bands. The obtained return loss are -15.6, -14.6 and -21dB for 4. 3, 7.4, 9.3 GHz and having bandwidth of 80, 300, and 410 MHz respectively. The measured gain of 3.88, 3.72 and 3.6dBi is obtained for the central frequency of 4.3,7.4,9.3 GHz [8]. The dual band two sided beam generation is produced by periodically modulated metasurface (MTS) and it is formed by array of split ring resonator [9]. The omnidirectional circularly polarised antenna is loaded with complementary V shaped slot is proposed. The antenna operates at 5.8GHz having bandwidth ranges from 5.65-5.75GHz and a peak gain of 1.26dBi [10]. A compact asymmetric coplanar waveguide (CPW) feed with split ring resonator is proposed to resonate at dual band for WLAN and WiMAX applications [11]. Different types of efficiencies for metasurface is introduced using single point source excitation [12].
A compact semi-circular monopole antenna loaded with complementary split ring resonator (CSRR) and two C-shaped slots [13] are introduced for GSM, WiMAX and C-band applications. A multiband monopole antenna based rectangular shaped complementary split ring resonator with offset-fed microstrip [14] is proposed for GSM and WLAN applications. In this paper [15] the design of compact penta band triangular patch antenna backed by hexagonal complementary split ring resonator for GPS, GSM, WLAN and WiMAX applications. For the gain improvement the microstrip patch antenna [16] with split ring resonator loaded ground plane is proposed for ISM band applications. The radiation pattern obtained in H-Plane is omnidirectional and in E-Plane is bidirectional.
The transmission lines loaded with split ring resonator (SRR) and complementary split ring resonator (CSRR) are arbitrarily oriented. The cross polarisation effect arises due to nonorthogonal alignment of the silt of the resonators [17]. A compact patch antenna is loaded with complementary split ring resonator (CSRR) and reactive impedance surface (RIS) and it provides multiband operations [18]. Patch antenna using split ring resonator at a resonant frequency of 4.67GHz and a size reduction of 29.3% is achieved with gain of 4.84dBi [19]. The microstrip patch antenna is loaded with complementary split ring resonator on the ground plane altering the effective medium parameters of the substrate [20]. The proposed antenna is discussed in section 2, simulated and measured results are discussed in section 3 and section 4 presents the conclusion.

PROPOSED ANTENNA
The microstrip patch antenna loaded with CSRR produce triple (C, X, Ku) band characteristics for wireless applications.
The proposed antenna design is simulated using Ansys HFSS and designed on FR4 epoxy glass substrate is suitable for PCB applications. The material is very low cost and has good mechanical properties. The proposed antenna having patch length and width of 38mm and 38mm and the height of the substrate is 1.6mm.

DESIGN EQUATION FOR PATCH
The width of the patch will be calculated from the following equation(1) where is the width of the patch, is the dielectric constant, is the velocity of light, 0 is the resonant frequency

DESIGN EQUATION SOLUTION FOR SQUARE SPLIT RING RESONATOR
Fig1a shows the structure of split ring resonator. Fig1b and 1c shows the proposed patch antenna loaded with 4 rings and 4 rings. Where Lin and Lout are the lengths of the outer and inner ring, W is the width of the metal ring, S is the space between the two rings and D is the opening of the rings or gap. The inductance Lm of each ring can obtained as, The value for = 60nH then find the value for Cm from the equation. After substituting all these values we get the value for Cm=75Ff.Assume the value for = =1mm for simplifying the calculation Then substituting the values for , , and 0 we get + = 47.77 .The Equilibrium constant (A) is found by using the following equation (4) The value for A= 0.03942.The dimension of the opening gap (D) is calculated by using the following formula (5) The value for D =1.14mm. Since it is a square patch the length and width are same. Table 1 shows the parameters of the proposed antenna with 4rings and 6 rings.        Table 2 and 3 shows the simulation results of the proposed antenna having 4rings and 6 rings. Table 4 shows the comparison with the previous work.   [4]. For X band at resonant frequency of 9.8510GHz the gain (in dBi) is improved and bandwidth is also improved by 2.73times compared to [4]. For Ku band having a resonant frequency of 13.7315GHz, bandwidth is improved by 4times compared to [5].

RESULTS AND DISCUSSION
From table 4 it is inferred that the proposed antenna with 6 rings having five resonant frequencies. For C band having resonant frequency of 7.7615GHz the gain (in dBi) is improved by 7.7times than [4]. For X band having resonant frequency of 9.5525GHz the gain is improved by 3.38times and bandwidth is improved by 2.83times than [4] and improvement in gain is achieved compared to [5]. For Ku band at a resonant frequency of 13.7315GHz, bandwidth is improved by 2.96 times than [5].

Funding
No funds or grants were received.

Conflicts of interest
The authors have no conflicts of interest to declare that are relevant to the content of this article.