DESIGN AND SIMULATION OF MICROSTRIP REFLECTARRAY ANTENNA: DTH (Ku BAND APPLICATION) Nitin Kumar
Assistant Professor, ECE Deptt. Sunderdeep Engineering College Ghaziabad (U.P) India
[email protected]
Abstract-
Today, most satellite TV customers in developed television markets get their programming through a direct broadcast satellite (DBS) provider, such as DISH TV or DTH platform. The provider selects programs and broadcasts them to subscribers as a set package. Basically, the provider’s goal is to bring dozens or even hundreds of channels to the customer’s television in a form that approximates the competition from Cable TV. Unlike earlier programming, the provider’s broadcast is completely digital, which means it has high picture and stereo sound quality. Early satellite television was broadcast in C-band - radio in the 3.4-gigahertz (GHz) to 7-GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (10 GHz to 14 GHz). Key-word: direct broadcast satellite, DTH, Cable TV, C-band, ku-band.
1. INTRODUCTION- The satellite DTH television delivery was the dream of futurists for decades, little technological progress was made before 1980. DTH service in the United States began, serendipitously, in 1979, when the FCC declared that receive- only terminal licensing was no longer mandatory and individuals started installing dishes, initially with a diameter >4 m, to receive signals intended for distribution to cable headends. From roughly 1985 to 1995, millions
of 2–3-m dishes were purchased individuals to receive this analog cable
by
feeds. Although the dish installations could cost several thousand dollars, the feeds were initially available without a monthly charge. The major challenges of all system designs have been the need to generate, within project cost constraints, sufficient satellite power levels into a practical dish size, and the need for reception electronics requirements consistent with consumer electronics price expectations [1]. Several planar antenna arrays have been proposed for direct to home (DTH) system [2-12]. Each has its own merits and drawbacks, whereas others have low-gain and/or low radiation efficiency. For DTH system, antenna should have bandwidth from 10GHz to 14GHz. The frequency range for this design should be 10.7 to 12.75GHZ, with a centre frequency of 11.725. the gain of this type of antenna should be equal to 36dB and the HPBW should be greater than 5.2 degree. Antenna should have perfect input impedance match with transmission line so that it radiate maximum power with VSWR less than 2 over the bandwidth. 2. ANTENNA DESIGN AND DISCUSSION We have design antenna using IE3D v.12 antenna simulator. Final dimension of proposed reflect-array Micro-strip Antenna with micro-strip line Feed is given in table below.
S. No.
Parameter
Value
1
Length of The radiator patch
5.22mm
2
Width of radiator patch
7.65mm
3
Length of feed strip
11.22mm
4
Width of feeding line
0.972mm
5
Relative dielectric constant
4.47
6
Thickness of substrate
1.6mm
7
Total no. of patch element
1024
The stub length of each patch is different depending on the equation
Different values of length(Δl) and relative permittivity (ε) gives stub length where effective wavelength (λ) is constant parameter and ψi is the required phase of
ith element to from a beam in broadside direction.
The stub length is calculated as follows: 8.88
8.57
7.95
7.03
5.82
5.08
2.55
0.51
1.76
4.2
7.01
9.9
13.1
16.4
19.5
23.6
8.57
1.13
15.8
298
0.12
1.95
20.8
19.8
19.7
13.5
18.8
9.0
13.3
6.1
23.9
6.9
7.95
15.8
12.7
8.05
9.4
18.2
3.5
3.7
4.0
3.9
1.6
3.1
2.4
1.5
0.5
0.7
7.03
2.98
8.05
16
3.57
10
4
0.6
5.4
10
15.7
11
14
5
6.1
5.06
5.82
1.9
18
10
8.9
8.4
8.4
2.7
9.1
9.8
11.5
11.8
13.1
17.9
12.8
8.7
5.08
0.12
9.4
3.5
12.2
8.9
2.7
5.7
10.6
2.35
3.8
7.3
10
0.8
1.9
2.4
2.55
20.8
3.5
4.01
8.45
10.6
2.3
5.4
8.72
0.95
1.9
2.7
3.15
10.6
4.17
5.35
0.51
24.5
3.7
0.69
8.45
2.3
5.43
10.7
2.33
3.23
5.25
10.2
8.75
2.3
9.7
0.47
1.76
29
4.0
5.4
2.77
3.8
10
2.33
3.6
7.75
10.3
1.7
2.9
3.8
2.6
2.87
4.2
13.5
3.9
10
9.1
7.3
2.3
3.23
8.9
0.73
2.92
3.51
3.8
7.35
4.75
6.37
7.01
18.6
1.6
15
9.8
10.3
3.9
5.75
0.73
2.57
3.51
5.77
9.4
10.3
10.76
11
9.9
9.0
3.1
11.9
11.5
0.8
8.7
10
2.9
3.51
5.93
8.35
10.7
0.8
2.13
1.59
13.1
13
2.4
14
11.8
1.9
0.95
1.7
3.5
5.94
8.35
0.57
1.34
1.95
2.15
2.93
16.4
6.1
1.5
5.6
13.1
2.1
1.9
2.9
3.8
9.47
10.7
1.38
2.07
2.47
2.79
3.38
19.5
23
0.5
6.12
17.9
2.47
2.7
2.6
4.7
10.7
2.13
2.15
2.79
2.5
3.89
3.72
23.6
6.9
0.7
5.06
8.7
2.5
3.15
2.8
6.3
11
1.59
2.93
3.38
3.87
3.72
1.87
Table: Calculated stub length for the element to compensate phase delay The table shown above is of 16x16 arrays this shows in the first half of XY plane. To obtain the 32x32 matrix similar table for remaining three quadrant of XY plane.
4. CONCLUSION AND RESULT All characteristics of antenna are carried out by IE3D simulator. Results are
discussed in the following sub sections one by one. I design the reflect array for the purpose of DTH the overall gain for this work is about 35dBi but for a single patch the gain is approx. 6dBi so for desire gain I used an array of radiating patch element. Figure 4: Antenna gain in E plane
Figure 1: Return loss with frequency
Antenna efficiency at resonance frequency is 90 % and always more than 65% over the bandwidth of 10 to14GHz as shown in figure 3. The gain for a single element is about 5dBi but over requirement is 35dBi so I use a 32x32 arrays for this purpose the graph of gain for reflect array is shown in the figure 4. The 3 D radiation pattern of the antenna shown in fig 5. This shows the satisfactory gain in desired direction.
Figure 2: VSWR with frequency. Figure 1 shows the return loss of reflect array which is approx. -28dB this loss is acceptable for DTH. Figure 2 shows the VSWR of antenna which is less than 2 over the given bandwidth and it is minimum at the centre frequency. Fig 5: 3-D Radiation pattern of antenna All above results such as impedance bandwidth, antenna efficiency more than 65%, antenna gain up to 35dBi are very satisfactory results for microstrip reflectarray antenna for DTH application. Fig 3: Efficiency of antenna with frequency
APPENDIX:
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(3) José A. Encinar, “Design of two layer printed reflect array using patch of variable size”, ieee transactions on antennas and propagation, vol. 49, no. 10, October 2001.
Michel CHARRIER, Afshin ZIAEI, “Low Loss Steerable Reflect-array antenna for Space application”,
(8) Fengchi e. Tsai
and marek e. Bialkowsk , “a unit cell waveguide approach to designing multi-layer reflect-arrays of variable size patches”,
(9) P. De Vita1, A. Freni1, G. Dassano, P. Pirinoli, R.E. Zich, “Broadband Printed Reflect-array Antenna”,
(4) Feng-Chi E. Tsai and Marek E.
(10) E.A. Soliman, A.M. Affandi, K.H. Badr,
Bialkowski, “Designing of 161 element Ku- band micro-strip reflect-array of variable size using an equivalent unit cell wave guide approach”, ieee transactions on antennas and propagation, vol. 51, no. 10, October 2003.
“Planar micro-strip antenna element and 2-by-2 sub-array for satellite TV receivers” , ieee transactions on antennas and propagation, page 4753, year 2008.
(5) Eva
Schwenzfeier, “broadband proximity-coupled and dual polarised micro-strip antenna for dth reception”, ieee transactions on antennas and propagation, December 1999.
(6) Jason
Stockmann and Richard Hodges, “The Use of Waveguide Simulators to Measure the Resonant Frequency of Ku-band Micro-strip Arrays”, IEEE transactions on antennas and propagation, October 2005.
(7) Hervey LEGAY, Beatrice PINTE, Etienne GIRARD, Raphael GILLARD,
(11) Adel Bedair Abdel, Mooty Abdel, Rahman, “Design and Development of High Gain Wideband Micro-strip Antenna”, international conference in Czech Technical University in year 2005.
(12) J. Huang, “Analysis of a Micro-strip Reflect-array Antenna for Microspacecraft Applications”, TDA Progress Report 42-120 February 15, 1995.
