blob: 159ce003ee7176831ecd2397cc67c90c6062cbdb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
//Chapter 15: Antennas for Special Applications
//Example 15-20.3
clc;
//Variable Initialization
f = 30e9 //Frequency (Hz)
Tr = 300 //Receiver temperature (K)
Ta = 275 //Satellite antenna temperature (K)
r = 1400e3 //Height (m)
c = 3e8 //Speed of light(m/s)
bw = 9.6e3 //Bandwidth per channel (Hz)
rcp_gain = 10 //RCP satellite gain (dBi)
rain_att = 10 //Rain attenuation (dB)
k = 1.4e-23 //Boltzmann's constant (J/K)
snr = 10 //Required SNR (dB)
ap_eff = 0.7 //Aperture efficiency (unitless)
Ta_2 = 10 //Dish antenna temperature (K)
//Calculations
wave_lt = c/f //Wavelength (m)
Ld = (wave_lt/(4*%pi*r))**2 //Spatial loss factor(unitless)
Ld_db = 10*log10(Ld) //Spatial loss factor(dB)
Tsys = Ta+Tr //System temperature (K)
N = k*Tsys*bw //Propagation loss due to rain (W)
N = 10*log10(N) //Propagation loss due to rain (dB)
Dr = -rcp_gain + snr - Ld_db + N + rain_att //Antenna gain (dB)
Dr = 10**(Dr/10) //Antenna gain (unitless)
Dr_req = Dr/ap_eff //Required antenna gain (unitless)
Dr_req_db = 10*log10(Dr_req) //Required antenna gain (dB)
dish_dia = 2*wave_lt*sqrt(Dr_req/28) //Required diameter of dish (m)
hpbw = sqrt(40000/Dr_req) //Half power beam width (degrees)
Tsys2 = Ta_2 + Tr //System temperature(K)
N2 = k*Tsys2*bw //Propagation loss due to rain(W)
N2 = 10*log10(N2) //Propagation loss due to rain(dB)
Pt_db = snr - Dr_req_db - rcp_gain + N2 - Ld_db + rain_att //Transmitted power (dB)
Pt = 10**(Pt_db/10)
//Results
mprintf("The Uplink antenna gain required is %d dB",Dr_req_db)
mprintf("\nThe Required dish size %.3f m",dish_dia)
mprintf("\nThe HPBW is %.1f degrees",hpbw)
mprintf("\nThe Downlink satellite power required is %.3f W", Pt)
|
