exercise 5.6

ZIP with MATLAB scripts and note:

exercise 5.6 notes:

Single series short circuit stub ZL=90+1j*60;Z0=75

D1 is transmission line length, fraction of wavelength: D1*lambda=L1, b1*l=2*pi*D1

D2 is Short Circuit Series Stub line length, fraction of wavelength: D2*lambda=L1, b2*l=2*pi*D2

ZL=90+1j*60;Z0=75;

Dstep=.001;drange=[0:Dstep:1];

D1=drange;D2=D1;

[D1,D2]=meshgrid(drange);

Z1=Z0*(ZL+1j*Z0*tan(2*pi*D1))./(Z0+1j*ZL*tan(2*pi*D1));

Zin_stub=Z0*1j*tan(2*pi*D2); % series sc stub

Zin=Z1+Zin_stub;

s11=(Zin-Z0)./(Zin+Z0);

surf(abs(s11),'LineStyle','none')

xlabel('D1');ylabel('D2');

ax.XTickLabelMode='manual';

ax.YTickLabelMode='manual';

ax.XTickLabel=[0:0.1:1];ax.YTickLabel=[0:0.1:1];

ax.XTick=[0:100:1000];ax.YTick=[0:100:1000];

ax=gca;ax.PlotBoxAspectRatio=[1 1 1]

V=1e3*del2(abs(s11));

figure(2);ax=gca;surf(V,'Lines','none');

xlabel('D1');ylabel('D2');

ax.XTickLabelMode='manual';

ax.YTickLabelMode='manual'; ax.XTickLabel=[0:0.1:1];ax.YTickLabel=[0:0.1:1];

ax.XTick=[0:100:1000];ax.YTick=[0:100:1000];

[pks,locs]=findpeaks(V(:),'Threshold',1);

[nd1,nd2]=ind2sub(size(V),locs);

hold all;figure(2);plot3(nd2,nd1,V(nd2,nd1)+2,'ro'); % plot peaks

ax.PlotBoxAspectRatio=[1 1 1] % box D1<.5 D2<.5

x0=find(drange==.5)

figure(2);plot3([x0 x0 0],[0 x0 x0],[.5 .5 .5],'Color',[1 0 0],'LineWidth',3)

abs(s11(sub2ind(size(V),nd1,nd2)))

=

0.001390798787950

0.002883920448033

0.001390798787950

0.002883920448033

unique(sort(drange(nd1)))'

unique(sort(drange(nd2)))'

numel(nd1)

D1=unique(drange(nd1))

D2=unique(drange(nd2))

Dstub1= D1([1 2]) % transmission lines shortest lengths

Dstub2= D2([1 2]) % series SC stub shortest lengths

= 0.103000000000000

0.397000000000000

0.603000000000000

0.897000000000000

= 0.174000000000000

0.482000000000000

0.674000000000000

0.982000000000000

= 8

D1 = 0.103 0.397 0.603 0.897

D2 = 0.174 0.482 0.674 0.982

Dstub1 = 0.103 0.397

Dstub2 = 0.174 0.482