JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN ELECTRONICS AND COMMUNICATION ENGINEERING
DESIGN AND DEVELOPEMENT MINIATURIZED PRINTED SLOT ANTENNA FOR C-BAND APPLICATIONS
1 HITESH CHAUKIKAR, 2 DR. KIRAN PARMAR, 3 DR. VED VYAS DWIVEDI
1M.Tech. Student, EC Department, L.D.college of Engineering, Ahmedabad, Gujarat,
2Professor, EC Department, L.D.college of Engineering, Ahmedabad, Gujarat, India
3Director, Noble Group of Institutions, Junagadh, Gujarat, India
, ,
ABSTRACT: This paper presents an optimization design for the rectangular printed antenna with slotted ground plane for c-band applications. A slot in the ground plane is shown to improve the bandwidth. The aim of this design is to develop a single antenna that can be used by all the IEEE 802.11 WLAN network standards collectively known as Wi-Fi. It is required to have a polarization complementary to that of multi-band printed monopole antennas, to achieve polarization diversity. The proposed antenna has a small size of 38.8 x 51.7 mm². The design is on FR- 4 substrate with dielectric constant of 4.4 and thickness 0.7 mm. Simulation is performed by using the HFSS software.
Keywords- Micro Strip-Line-Fed Antennas, Bandwidth Enhancement, Printed Slot Antennas.
ISSN: 0975 –6779| NOV 10 TO OCT 11 | VOLUME – 01, ISSUE - 02 Page 102
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN ELECTRONICS AND COMMUNICATION ENGINEERING
1. INTRODUCTION
The popularity of wireless communication systems has increased significantly in the last decade as evident from applications such as mobile phones and wireless networks. As the demand for these systems increases, there is a need for advanced antennas and antenna systems with new capabilities and better performance. A single antenna that can support multiple communication services such as mobile phone, Wi-Fi WLAN, Bluetooth etc. is an example. Such an antenna would allow a wireless device with multiple wireless applications to utilise a single antenna element to transmit and receive signals. By only having a single antenna element, the space required for antennas on the device is reduced significantly. There have been designs of antennas operating in dual-band in order to accommodate this. Some examples of these antennas are fractal antenna, printed slot antenna, planar monopole, and printed inverted-F antenna. These antennas are capable in operating in dual to quad bands. Furthermore, Printed slot antennas are attractive because of their wide impedance bandwidths, low cost, planar structures and easy integration with active devices or MMICs. Thus, great interest in various printed slot antennas can be seen in the literature. In recent years, some micro strip-line-fed printed slot antennas [1]–[4] have been reported because of their favourable impedance characteristics. In the reported literature [4], a printed\slot antenna with a fork-like tuning stub has been shown to have a good bandwidth enhancement. However, it is not enough for the operating bandwidth to cover more wireless communication services. In this paper, a new design of micro strip- line-fed printed slot antenna with slotted ground plane. In this design, The size of the ground plane is same as the substrate size. By choosing proper dimensions of the ground plane and parasitic strips, it is seen that more resonant modes operating near the centre frequency of the conventional slot antenna can be obtained. With these resonant modes, the proposed antenna can have similar radiation patterns and the same polarization. From the experimental results, the obtained impedance bandwidth (10 dB return loss) of the proposed antenna can operate from 4 to 8 GHz with a centre frequency at around 5.2 GHz.
2. design considerations of proposed printed slot antenna
In this paper, these proposed antennas are fabricated on a 0.7-mm thick FR-4 substrate with a dielectric constant of εr = 4.4 and tan δ = 0.002. The slot is etched on the ground plane of the substrate as a radiating element. The length L of the slot of the antenna 1 is determined to be λg /2 (where λg is the guided wavelength at 5.2 GHz) in order to obtain a maximum power at the broadside direction. A micro strip-fed line on the bottom plane of the substrate is as a probe excitation of the slot antenna to excite the slot mode.
Fig. 1 shows the geometry of the proposed printed slot antenna for C-Band applications. The antenna is printed on the top portion of the system circuit board of the mobile phone, whose dimensions are selected to be 38.8 mm in length and 51.7 mm in width. The selected dimensions are reasonable for general mobile phone’s wifi, and in this study the circuit board is fabricated using a 0.7-mm-thick FR4 substrate of relative permittivity 4.4 and loss tangent 0.002.The ground plane is on the top of the substrate. The slot is cut in the ground plane that’s why improving the band width of the system.
Fig.1 Geometry of the Printed Slot Antenna
Fig. 2 Final HFSS Model of the Printed Slot Antenna
Table:1 Calculated parameters of Printed Slot Antenna
Name of the Parameters / Values( in mm)Substrate (FR4) / ε r = 4.4
Substrate length(L) / 38.8
Substrate width(W) / 51.7
Ground length / 38.8
Ground width / 51.7
Micro strip offset for antenna-1 / 7.90
Micro strip offset for antenna-2 / 7.52
Micro strip offset for antenna-3 / 8.32
Effects of different parameters in the antenna structures on antenna bandwidth have been examined. By varying these parameters, the resonance frequencies of the antenna can be altered to meet the required specifications. InTable-1, the value of the all parameters is given. The length of the L-Shaped Antenna-2 and Antenna-3 are same as the Length of the Antenna-1 that is λg /2. At present, the communication systems require really high performance antennas; side lobe and cross polar levels should be reduced in the radiation pattern as well as the size of the antenna.
3. Equation for geometry of the printed slot antenna
The length of linear slot antenna L1 is designed for 2.44 GHz which referred with wavelength in the substrate ¸λg that can be calculated by following:
(1)
(2)
Where ε r is the effective dielectric constant,
(3)
In this case, λg = 57.69 mm at frequency 5.2 GHz.
Fig. 3 Microstrip Feed
The width of micro strip line is designed for match impedance with the characteristic impedance of transmission line 50 ohms which can be calculated by following
(4)
where and Z0 is characteristic impedance.
In this case, width of micro strip line: W = 27.945 mm.At designed frequency of 5.2 GHz, the length of slot antenna L1 = 25.935 (0.37 λg). The width of linear slot antenna W1 is varied in five values beginning from 2.5mm to 5mm by step up 0.5 mm, and Lm1 is adjusted for match impedance. The simulation results of return loss S11, resonance frequency, frequency range and bandwidth are tabulated in Table 1. It shows that the changing in width of slot antenna will affect on the resonance the same resonance frequency and wider bandwidth. When the width of slot is increased, the resonance frequency will decrease and bandwidth is wider. Therefore, if we increase the width of slot, the length of slot should be decreased in order to achieve.
3. Measurements and Results
The simulation of Printed Slot Antenna was obtained by using HFSS. It integrates simulation, visualization, solid modelling, and automation in an easy-to-learn environment where solutions to your 3D EM problems are quickly and accurately obtained. Simulations show a very small return loss, lower than -25 dB in the frequency band of 4 GHz to 8 GHz as shown in figure 4. The antenna has very low side lobe level, lower than 36 dB as shown in figure 5. The measured and simulated E patterns, return loss, VSWR plot have a good agreement.
Fig. 4 Return Loss
Fig. 5 Radiation Pattern
Fig. 6 E Gain
Figure 7 shown the simulated and measured 3D Radiation patterns. The colours in the figures show the power level and the E mode pattern is as shown in figure 6.
Fig. 7 3D Radiation Patterns
Fig. 8 3D LHCP and RHCP gain
4. Fig 9 VSWR
4. SUMMERY
The papers discussed the design of printed slot antennas operating in the 4.2GHz and 5.4GHz bands to accommodate IEEE 802.11a WLAN standards. Effects of different parameters in the antenna structures on antenna bandwidth have been examined. By varying these parameters, the resonance frequencies of the antenna can be altered to meet the required specifications. This multi-band printed slot antenna appears to be a promising companion to previous multi-band printed monopole antennas in providing polarization diversity
A small, planar, dual-band, low-cost, and easy to manufacture WLAN antenna having UWB functionality is presented in this report. The WLAN antenna achieves excellent dual-band operation and can be built on other types of microwave substrates as well. It can be positioned at the edge of a PCB of a notebook computer, or any other wireless equipment.
5. REFERENCES
[1] Jan and Jia-Wei Su ” Bandwidth Enhancement of a Printed Wide-Slot Antenna With a Rotated Slot” IEEE Transactions On Antennas And Propagation, Vol. 53, No. 6, June 2005.
[2] Yong Cheng*, Wen-jun Lu,Chong-hu Cheng” Printed Diversity Antenna for Ultra-wideband Applications” College of Electronic Science & Engineering, Jiangsu Key Laboratory of Wireless Communications, Nanjing University of Posts & Telecommunications, Nanjing, Jiangsu, China.
[3] Kildas p.-s.,” Gaussian beam model for aperture controlled and flareangle-controlled corrugated horn antenna ”, IEEE Proceedings, Vol.135, pt.H, No.4,August 1988
ISSN: 0975 –6779| NOV 10 TO OCT 11 | VOLUME – 01, ISSUE - 02 Page 102