slotted waveguide antenna

  1 %% waveguide slot equvalient circuit
  2 % Leon yangli0534@yahoo.com
  3 clc;
  4 clear all;
  5 close all;
  6 format long;
  7 %% constants
  8 N = 12; %slot numbers
  9 SLL = -25; % sidelobe level
 10 u0 = 4*pi*1e-7;% permeability
 11 e0 = 8.854187817e-12;% permittivity in free space
 12 c = 1/sqrt(u0*e0);% light velocity in free space
 13 %% parameters
 14 f0 = 9e9;% frequency
 15 l = c/f0*1e3; % lambda in free space
 16 % a = 247.65; % width length in mm
 17 % b = a/2 ;% height length in mm
 18 %WR-284
 19 % a = 20;
 20 % b = 10;
 21  a = 22.86;
 22  b = 10.16;
 23 %a = 7.112 ; %waveguide width
 24 %b = 3.556 ; % waveguide height
 25 
 26 t = 1 ;% thickness in mm
 27 w = a*0.0625/0.9 ;% width of the slot in mm l/200 < w < l/10
 28 lc = 2*a ; % cutoff lambda
 29 lg = l/sqrt(1-(l/lc)^2); % waveguide wavelength
 30 
 31 G_2_slot=1.0/N;
 32 New_G1=2.09*(lg/l)*(a/b)*(cos(0.464*pi*l/lg)-cos(0.464*pi))^2;
 33 New_Y=G_2_slot/New_G1;
 34 Soff=(a/pi)*sqrt(abs(asin(New_Y)));% offset distance
 35 
 36 Slot_wl=0.210324*G_2_slot^4-0.338065*G_2_slot^3+0.12712*G_2_slot^2+0.034433*G_2_slot+0.48253;
 37 l_slot=l*Slot_wl;%slot length
 38 w_slot=a*0.0625/0.9;%slot width
 39 s_slot=lg/2 ; % space betwenn slots
 40 
 41 
 42 d = linspace(0,a/2,1000)+1e-10;
 43 %% stevenson 利用等效传输线理论和格林函数，推导了归一化电导
 44 g = 2.09*a*lg/b/l*power(cos(pi/2*l/lg),2)*power(sin(pi/a*d),2);
 45 
 46 %% H.Y.Yee计算方法解决了谐振长度随偏移距离变化的问题
 47 beta = 2*pi/lg; % TE10模传播常数 
 48 Y0 = beta/f0/2/pi/u0;%波导特征导纳
 49 %考虑缝隙影响，把缝隙看成一段分支波导
 50 
 51 
 52 
 53 % figure(1);
 54 % plot(d,g,'k');
 55 % grid on;
 56 % grid minor;
 57 % title('宽边纵缝的归一化谐振电导与偏置量的变化 ');
 58 % xlabel('偏置距离:mm');
 59 % ylabel('归一化电导')
 60 % 
 61 
 62 
 63 
 64 [BeamWidth, D, I]= dolph_chebyshev(N,SLL,0);
 65 figure;
 66 subplot(221);
 67 plot(I,'-o');
 68 
 69 title('Dolph-Chebyshev 综合');
 70 hold on;
 71 [af,bw,gain] = radiation_pattern(I);
 72 len = length(af);
 73 angle = linspace(-90,90,len);
 74 subplot(222);
 75 plot(angle,af);
 76 ylim([-60 0]);
 77 grid on;
 78 title('方向图')
 79 text(20,5,bw);
 80 g = I.^2/sum(I.^2);
 81 g = I/sum(I);
 82 % 
 83 %figure;
 84 subplot(223)
 85 plot(g,'k*');
 86 title('等效电导')
 87 hold on;
 88 % % g = a/b*2.09*lg/l*power(cos(pi*l/lg/2),2)*power(sin(pi*x/a),2)
 89  x = a/pi*asin(sqrt(g/(2.09*a/b*lg/l*power(cos(pi/2*l/lg),2))));
 90 %figure;
 91 subplot(224)
 92 plot(x,'r*');
 93 title('缝隙偏移')
 94 
 95 %%
 96 %Taylor one parameter
 97 I= taylor_one_para(N,SLL);
 98 figure;
 99 subplot(221);
100 plot(I,'-o');
101 
102 title('taylor单变量综合');
103 hold on;
104 [af,bw,gain] =  radiation_pattern(I);
105 len = length(af);
106 angle = linspace(-90,90,len);
107 subplot(222);
108 plot(angle,af);
109 ylim([-60 0]);
110 grid on;
111 title('方向图')
112 text(20,5,bw);
113 g = I.^2/sum(I.^2);
114 g = I/sum(I);
115 % 
116 %figure;
117 subplot(223)
118 plot(g,'k*');
119 title('等效电导')
120 hold on;
121 % % g = a/b*2.09*lg/l*power(cos(pi*l/lg/2),2)*power(sin(pi*x/a),2)
122  x = a/pi*asin(sqrt(g/(2.09*a/b*lg/l*power(cos(pi/2*l/lg),2))));
123 %figure;
124 subplot(224)
125 plot(x,'r*');
126 title('缝隙偏移')
127 
128 %%
129 %taylor line source
130 I= taylor_line(N,SLL);
131 figure;
132 subplot(221);
133 plot(I,'-o');
134 
135 title('taylor线源综合');
136 hold on;
137 [af,bw,gain] =  radiation_pattern(I);
138 len = length(af);
139 angle = linspace(-90,90,len);
140 subplot(222);
141 plot(angle,af);
142 ylim([-60 0]);
143 grid on;
144 title('方向图')
145 text(20,5,bw);
146 g = I.^2/sum(I.^2);
147 g = I/sum(I);
148 % 
149 %figure;
150 subplot(223)
151 plot(g,'k*');
152 title('等效电导')
153 hold on;
154 % % g = a/b*2.09*lg/l*power(cos(pi*l/lg/2),2)*power(sin(pi*x/a),2)
155  x = a/pi*asin(sqrt(g/(2.09*a/b*lg/l*power(cos(pi/2*l/lg),2))));
156 %figure;
157 subplot(224)
158 plot(x,'r*');
159 title('缝隙偏移')
View Code