Question

Design microstrip circular array antenna in HFSS software and MATLAB CODE FOR IT.

Design microstrip circular array antenna in HFSS software and MATLAB CODE FOR IT.

IF YOU KNOW THEN ONLY DO OR ELSE LEAVE FOR OTHER

ANTENNA ,ELECTRICAL ENGINEERING

Answer 1

%*******************************************************************

% MICROSTRIP

%*******************************************************************

% THIS PROGRAM IS A MATLAB PROGRAM THAT DESIGNS AND THEN COMPUTES THE

% ANTENNA RADIATION CHARACTERISTICS OF:

%

% I. RECTANGULAR

% II. CIRCULAR

%

% MICROSTRIP PATCH ANTENNAS BASED ON THE CAVITY MODEL AND DOMINANT

% MODE OPERATION FOR EACH. THAT IS:

%

% A. TM(010) MODE FOR THE RECTANGULAR PATCH

% B. TM(011) MODE FOR THE CIRCULAR PATCH

%

% ** INPUT PARAMETERS

% 1. FREQ = RESONANT FREQUENCY (in GHz)

% 2. EPSR = DIELECTRIC CONSTANT OF THE SUBSTRATE

% 3. HEIGHT = HEIGHT OF THE SUBSTRATE (in cm)

% 4. Y0 = POSITION OF THE RECESSED FEED POINT (in cm)

% RELATIVE TO LEADING RADIATING EDGE OF RECTANGULAR

% PATCH. NOT NECESSARY FOR CIRCULAR PATCH.

%

% ** OUTPUT PARAMETERS

% A. RECTANGULAR PATCH:

%

% 1. PHYSICAL WIDTH OF THE PATCH W (in cm)

% 2. EFFECTIVE LENGTH OF PATCH Le (in cm)

% 3. PHYSICAL LENGTH OF PATCH L (in cm)

% 4. NORMALIZED E-PLANE AMPLITUDE PATTERN (in dB)

% 5. NORMALIZED H-PLANE AMPLITUDE PATTERN (in dB)

% 6. E-PLANE HALF-POWER BEAMWIDTH (in degrees)

% 7. H-PLANE HALF-POWER BEAMWIDTH (in degrees)  

% 8. DIRECTIVITY (dimensionless and in dB)

% 9. RESONANT INPUT RESISTANCE (in ohms)

% a. AT LEADING RADIATING EDGE (y = 0)

% b. AT RECESSED FEED POINT FROM LEADING RADIATING EDGE

% (y = yo)

%

% B. CIRCULAR PATCH:

%

% 1. PHYSICAL RADIUS OF THE PATCH a (in cm)

% 2. EFFECTIVE RADIUS OF THE PATCH ae (in cm)

% 3. NORMALIZED E-PLANE AMPLITUDE (in dB)

% 4. NORMALIZED H-PLANE AMPLITUDE (in dB)

% 5. E-PLANE HALF-POWER BEAMWIDTH (in degrees)

% 6. H-PLANE HALF-POWER BEAMWIDTH (in degrees)

% 7. DIRECTIVITY (dimensionless and in dB)

%

%*******************************************************************

% Programmed by : Sung-Woo Lee , Arizona State University

% Modified by : Zhiyong Huang, Arizona State University

% Nov. 23, 2004

%*******************************************************************

function []=MICROSTP;

clear all;

close all;

warning off;

option=[];

while isempty(option)|(option~=1&option~=2),

option=input(['SELECT OUTPUT METHOD\n',' OPTION (1): SCREEN\n',' OPTION (2): OUTPUT FILE\n', ...

'SELECT OPTION: ']);

end;   

filename=[];

if option==2,

while isempty(filename),

filename=input('INPUT THE DESIRED OUTPUT FILENAME <in single quotes> = ','s');

end;

end;

addpath(pwd);

if exist(filename,'file')&isa(filename,'char'),

delete(filename);

end;

rmpath(pwd);

patchm=[];

while isempty(patchm)|((patchm~=1)&(patchm~=2)),

patchm=input(['PATCH GEOMETRY OPTION\n',' OPTION (1) : RECTANGULAR PATCH\n', ...

' OPTION (2) : CIRCULAR PATCH\n','SELECT OPTION NUMBER: ']);

end;

if (patchm==1), % Rectangular

rect(option,filename);

else % Circular   

circ(option,filename);

end;

warning on;

%%%%%%%%%%%%%%%%%%%

function rect=rect(option_a,filename);

%%%%%%%%%%%%%%%%%%%

% Input Parameters (freq, epsr, height, Yo)

freq=[];

while isempty(freq),

freq=input('INPUT THE RESONANT FREQUENCY (in GHz) = ');

end;

er=[];

while isempty(er),

er=input('INPUT THE DIELECTRIC CONSTANT OF THE SUBSTRATE = ');

end;

h=[];

while isempty(h),

h=input('INPUT THE HEIGHT OF THE SUBSTRATE (in cm) = ');

end;

option1=[];

while isempty(option1)|(option1~=1&option1~=2),

option1=input(['OPTIONS \n',' OPTION (1): FIND INPUT IMPEDANCE Zin AT FEED-POINT Yo \n', ...

' OPTION (2): DETERMINE Yo FOR A GIVEN DESIRED Zin \n', ...

'SELE1CT OPTION NUMBER: ']);

end;

if option1==1

Yo=[];

while isempty(Yo),

Yo=input(['\nINPUT THE POSITION OF THE RECESSED FEED POINT ' ...

'RELATIVE TO THE LEADING RADIATING EDGE\n' 'OF THE RECTANGULAR PATCH (in cm) = ']);

  

end

else

Zin=[];

while isempty(Zin),

Zin=input(['INPUT THE DESIRED INPUT IMPEDANCE Zin (in ohms) = ']);

end

end

% Compute W, ereff, Leff, L (in cm)

W=30.0/(2.0*freq)*sqrt(2.0/(er+1.0));

ereff=(er+1.0)/2.0+(er-1)/(2.0*sqrt(1.0+12.0*h/W));

dl=0.412*h*((ereff+0.3)*(W/h+0.264))/((ereff-0.258)*(W/h+0.8));

lambda_o=30.0/freq;

lambda=30.0/(freq*sqrt(ereff));

Leff=30.0/(2.0*freq*sqrt(ereff));

L=Leff-2.0*dl;

ko=2.0*pi/lambda_o;

Emax=sinc(h*ko/2.0/pi);

% Normalized radiated field

% E-plane pattern : 0 < phi < 90 ; 270 < phi < 360

% H-plane pattern : 0 < th < 180

phi=0:360; phir=phi.*pi./180; [Ethval,Eth]=E_th(phir,h,ko,Leff,Emax);

th=0:360; thr=th.*pi/180.0; [Ephval,Eph1]=E_ph(thr,h,ko,W,Emax);

Eph(1:91)=Eph1(91:181); Eph(91:270)=Eph1(181); Eph(271:361)=Eph1(1:91);

% Output files

fid_e=fopen('Epl-Micr_m.dat','wt');

fid_h=fopen('Hpl-Micr_m.dat','wt');

fprintf(fid_e,'# E-PLANE RADIATION PATTERN\n');

fprintf(fid_e,'# -------------------------\n#\n');

fprintf(fid_h,'# H-PLANE RADIATION PATTERN\n');

fprintf(fid_h,'# NOTE: THIS PATTERN IS ROTATED CCW BY 90 DEGREES\n');

fprintf(fid_h,'# -------------------------\n#\n');

Epl=[phi;Eth];

fprintf(fid_e,' %7.4f\t%7.4f\n',Epl);

fclose(fid_e);

Hpl=[[0:90 270:360];[Eph(1:91) Eph(271:361)]];

fprintf(fid_h,' %7.4f\t%7.4f\n',Hpl);

fclose(fid_h);

% Plots of Radiation Patterns

% Figure 1

% ********

Etheta=[Eth(271:361),Eth(2:91)];

xs=[0 20 40 60 80 90 100 120 140 160 180];

xsl=[270 290 310 330 350 0 10 30 50 70 90];

hli1=plot(Etheta,'b-');

set(gca,'Xtick',xs);

set(gca,'Xticklabel',xsl);

set(gca,'position',[0.13 0.11 0.775 0.8]);

h1=gca; h2=copyobj(h1,gcf);

xlim([0 180]);ylim([-60 0]);

set(h1,'xcolor',[0 0 1]); set(hli1,'erasemode','xor'); hx=xlabel('\phi (degrees)','fontsize',12);

axes(h2); hli2=plot(Eph1,'r:'); axis([0 180 -60 0]);

set(h2,'xaxislocation','top','xcolor',[1 0 0]);

legend([hli1 hli2],{'E_{\phi} (E-plane)','E_{\phi} (H-plane)'},4);

xlabel('\theta (degrees)','fontsize',12);

set([hli1 hli2],'linewidth',2); set(hx,'erasemode','xor');

ylabel('Radiation patterns (in dB)','fontsize',12);

% title('E- and H-plane Patterns of Rectangular Microstrip Antenna','fontsize',[12]);

% Figure 2

% ********

figure(2);

hp1=semipolar_micror(phir,Eth,-60,0,4,'-','b'); hold on;

hp2=semipolar_micror(phi*pi/180,Eph,-60,0,4,':','r');

title('E- and H-plane Patterns of Rectangular Microstrip Antenna','fontsize',[12]);

hle=legend([hp1 hp2],{'E_{\phi} (E-plane)','E_{\phi} (H-plane)'},0);

% E-plane HPBW and H-plane HPBW

% ******************************

an=phi(Eth>-3);

an(an>90)=[];

EHPBW=2*abs(max(an));

HHPBW=2*abs(90-min(th(Eph1>-3)));

% Directivity

[D,DdB]=dir_rect(W,h,Leff,L,ko);

% Input Impedance at Y=0 and Y=Yo

[G1,G12]=sintegr(W,L,ko);

Rin0P=(2.*(G1+G12))^-1;

Rin0M=(2.*(G1-G12))^-1;

if option1==1

RinYoP=Rin0P*cos(pi*Yo/L)^2;

RinYoM=Rin0M*cos(pi*Yo/L)^2;

else

YP=acos(sqrt(Zin/Rin0P))*L/pi;

YM=acos(sqrt(Zin/Rin0M))*L/pi;

end

% Display (rectangular)

clc;

if(option_a==2)

diary(filename);

end

disp(strvcat('INPUT PARAMETERS','================'));

disp(sprintf('\nRESONANT FREQUENCY (in GHz) = %4.4f',freq));

disp(sprintf('DIELECTRIC CONSTANT OF THE SUBSTRATE = %4.4f',er));

disp(sprintf('HEIGHT OF THE SUBSTRATE (in cm) = %4.4f',h));

if option1==1

disp(sprintf('POSITION OF THE RECESSED FEED POINT (in cm) = %4.4f\n',Yo));

else

fprintf('DESIRED RESONANT INPUT INPEDANCE (in ohms) = %4.4f\n', Zin);

end

disp(strvcat('OUTPUT PARAMETERS','================='));

disp(sprintf('\nPHYSICAL WIDTH OF PATCH (in cm) = %4.4f',W));

disp(sprintf('EFFECTIVE LENGH OF PATCH (in cm) = %4.4f',Leff));

disp(sprintf('PHYSICAL LENGH OF PATCH (in cm) = %4.4f',L));

disp(sprintf('E-PLANE HPBW (in degrees) = %4.4f',EHPBW));

disp(sprintf('H-PLANE HPBW (in degrees) = %4.4f',HHPBW));

disp(sprintf('DIRECTIVITY OF RECTANGULAR PATCH (dimensionless) = %4.4f',D));

disp(sprintf('DIRECTIVITY OF RECTANGULAR PATCH (in dB) = %4.4f\n',DdB));

disp(sprintf('G1 (Using (14-12)) = %4.8f', G1));

disp(sprintf('G12 (Using (14-18a)) = %4.8f\n', G12));

disp(sprintf('RESONANT INPUT RESISTANCE AT LEADING RADIATING EDGE (y=0) Rin0P (Using + sign in (14-17)) = %4.4f ohms',Rin0P));

disp(sprintf('RESONANT INPUT RESISTANCE AT LEADING RADIATING EDGE (y=0) Rin0M (Using - sign in (14-17)) = %4.4f ohms\n',Rin0M));

if option1==1

fprintf('RESONANT INPUT RESISTANCE AT RECESSED FEED POINT (y=%4.4f cm) RinYoP (Using + sign in (14-17)) = %4.4f ohms\n',Yo, RinYoP);

fprintf('RESONANT INPUT RESISTANCE AT RECESSED FEED POINT (y=%4.4f cm) RinYoM (Using - sign in (14-17)) = %4.4f ohms\n\n',Yo, RinYoM);

else

fprintf('FOR DESIRED IMPENDANCE %4.4f ohms, THE FEED POINT POSITION YoP (Using + sign in (14-17)) = %4.4f cm\n',Zin, YP);

fprintf('FOR DESIRED IMPENDANCE %4.4f ohms, THE FEED POINT POSITION YoM (Using - sign in (14-17)) = %4.4f cm\n\n',Zin, YM);

end

disp(strvcat('*** NOTE:',...

' THE E-PLANE AMPLITUDE PATTERN IS STORED IN Epl-Micr_m.dat',...

' THE H-PLANE AMPLITUDE PATTERN IS STORED IN Hpl-Micr_m.dat',...

' ========================================================='));

diary off;

% Subfunctions

% ************

function [Ethval,Eth]=E_th(phir,h,ko,Leff,Emax)

ARG=cos(phir).*h.*ko./2;

Ethval=(sinc(ARG./pi).*cos(sin(phir).*ko*Leff./2))./Emax;

Eth=20*log10(abs(Ethval));

Eth(phir>pi/2&phir<3*pi/2)=-60;

Eth(Eth<=-60)=-60;

function [Ephval,Eph1]=E_ph(thr,h,ko,W,Emax)

ARG1=sin(thr).*h.*ko./2;

ARG2=cos(thr).*W.*ko./2;

Ephval=sin(thr).*sinc(ARG1./pi).*sinc(ARG2./pi)./Emax;

Eph1=20.0*log10(abs(Ephval));

Eph1(Eph1<=-60)=-60;

function [D,DdB]=dir_rect(W,h,Leff,L,ko)

th=0:180; phi=[0:90 270:360];

[t,p]=meshgrid(th.*pi/180,phi.*pi/180);

X=ko*h/2*sin(t).*cos(p);

Z=ko*W/2*cos(t);

Et=sin(t).*sinc(X/pi).*sinc(Z/pi).*cos(ko*Leff/2*sin(t).*sin(p));

U=Et.^2;

dt=(th(2)-th(1))*pi/180;

dp=(phi(2)-phi(1))*pi/180;

Prad=sum(sum(U.*sin(t)))*dt*dp;

D=4.*pi.*max(max(U))./Prad;

DdB=10.*log10(D);

function [G1,G12]=sintegr(W,L,ko)

th=0:1:180; t=th.*pi/180;

ARG=cos(t).*(ko*W/2);

res1=sum(sinc(ARG./pi).^2.*sin(t).^2.*sin(t).*((pi/180)*(ko*W/2)^2));

res12=sum(sinc(ARG./pi).^2.*sin(t).^2.*besselj(0,sin(t).*(ko*L)).*sin(t).*((pi/180)*(ko*W/2)^2));

G1=res1./(120*pi^2); G12=res12./(120*pi^2);

%%%%%%%%%%%%%%%%%%%

function circ=circ(option_a,filename);

%%%%%%%%%%%%%%%%%%%

% Input Parameters (freq, epsr, height)

freq=[];

while isempty(freq),

freq=input('INPUT THE RESONANT FREQUENCY (in GHz) = ');

end;

er=[];

while isempty(er),

er=input('INPUT THE DIELECTRIC CONSTANT OF THE SUBSTRATE = ');

end;

h=[];

while isempty(h),

h=input('INPUT THE HEIGHT OF THE SUBSTRATE (in cm) = ');

end;

con=input('PLEASE INPUT THE CONDUCTIVITY (DEFAULT VALUE IS 10^7):');

if isempty(con)

con=10^7;

end

lt=input('PLEASE INPUT THE LOST TANGENT (DEFAULT VALUE OF DOMNINANT MODE TM110 IS 0.0018):');

if isempty(lt)

lt=0.0018;

end

%input of the rho0 or zin

option1=[];

while isempty(option1)|(option1~=1&option1~=2),

option1=input(['OPTIONS \n',' OPTION (1): FIND INPUT IMPEDANCE Zin AT FEED-POINT RHOo \n', ...

' OPTION (2): DETERMINE RHOo FOR A GIVEN DESIRED Zin \n', ...

'SELE1CT OPTION NUMBER: ']);

end;

if option1==1

RHOo=[];

while isempty(RHOo),

RHOo=input(['\nINPUT THE POSITION OF THE RECESSED FEED POINT ' ...

'RELATIVE TO THE CENTER OF THE CIRCULAR PATCH (in cm) = ']);

  

end

else

Zin=[];

while isempty(Zin),

Zin=input(['INPUT THE DESIRED INPUT IMPEDANCE Zin (in ohms) = ']);

end

end

% Compute the Physical Radius a (in cm) and Effective Radius ae (in cm)

lambda_o=30.0/freq;

ko=2.0*pi/lambda_o;

F=8.791/(freq*sqrt(er));

a=F/sqrt(1+2*h/(pi*er*F)*(log(pi*F/(2*h))+1.7726));

ae=a*sqrt(1+2*h/(pi*er*a)*(log(pi*a/(2*h))+1.7726));

% Normalized radiated field

% E-plane and H-plane patterns : 0 < th < 90

th=0:90; thr=th.*pi./180;

x=sin(thr).*ko.*ae;

J0=besselj(0,x);

J2=besselj(2,x);

Eth1=J0-J2;

Eph1=(J0+J2).*cos(thr);

Eth2=20.*log10(Eth1./max(Eth1));

Eph2=20.*log10(Eph1./max(Eph1));

Eth2(Eth2<=-60)=-60;

Eph2(Eph2<=-60)=-60;

Eth(1:91)=Eth2(1:91); Eth(91:270)=Eth2(91); Eth(271:361)=Eth2(91:-1:1);

Eph(1:91)=Eph2(1:91); Eph(91:270)=Eph2(91); Eph(271:361)=Eph2(91:-1:1);

% Output files

fid_e=fopen('Epl-Micr_m.dat','wt');

fid_h=fopen('Hpl-Micr_m.dat','wt');

fprintf(fid_e,'# E-PLANE RADIATION PATTERN\n');

fprintf(fid_e,'# -------------------------\n#\n');

fprintf(fid_h,'# H-PLANE RADIATION PATTERN\n');

fprintf(fid_h,'# -------------------------\n#\n');

Epl=[[0:90 270:360];[Eth(1:91) Eth(271:361)]];

fprintf(fid_e,' %7.4f\t%7.4f\n',Epl);

fclose(fid_e);

Hpl=[[0:90 270:360];[Eph(1:91) Eph(271:361)]];

fprintf(fid_h,' %7.4f\t%7.4f\n',Hpl);

fclose(fid_h);

% Plots of Radiation Patterns

phi=0:360;

% Figure 1

% ********

hli1=plot(-90:90,[fliplr(Eth2) Eth2(2:end)],'b-'); set(gca,'position',[0.13 0.11 0.775 0.8]);

h1=gca; h2=copyobj(h1,gcf); axis([-90 90 -60 0]);

set(h1,'xcolor',[0 0 1]); set(hli1,'erasemode','xor'); hx=xlabel('\theta (degrees)','fontsize',12);

axes(h2); hli2=plot(-90:90,[fliplr(Eph2) Eph2(2:end)],'r:'); axis([-90 90 -60 0]);

set(h2,'xaxislocation','top','xcolor',[1 0 0]);

set([hli1 hli2],'linewidth',2);

legend([hli1 hli2],{'E_{\theta} (E-plane)','E_{\phi} (H-plane)'},4);

xlabel('\theta (degrees)','fontsize',12);

% Figure 2

% ********

figure(2);

thr=(-90:90)*pi/180;

hp1=semipolar_microc(thr,[fliplr(Eth2) Eth2(2:end)],-60,0,4,'-','b'); hold on;

hp2=semipolar_microc(thr,[fliplr(Eph2) Eph2(2:end)],-60,0,4,':','r');

hle=legend([hp1 hp2],{'E_{\theta} (E-plane)','E_{\phi} (H-plane)'},0);

title('E- and H-plane Patterns of Circular Microstrip Antenna','fontsize',[12]);

% E-plane and H-plane HPBW

an=th(Eth2>-3);

bn=th(Eph2>-3);

EHPBW=2*abs(max(an));

HHPBW=2*abs(max(bn));

%resonant input resistance

t=[0:0.001:pi/2];

x=ko*ae*sin(t);

j0=besselj(0,x);

j2=besselj(2,x);

j02p=j0-j2;

j02=j0+j2;

grad=(ko*ae)^2/480*sum((j02p.^2+(cos(t)).^2.*j02.^2).*sin(t).*0.001);

emo=1;

m=1;

mu0=4*pi*10^(-7);

k=ko*sqrt(er);

gc=emo*pi*(pi*mu0*freq*10^9)^(-3/2)*((k*ae)^2-m^2)/(4*(h/100)^2*sqrt(con));

gd=emo*lt*((k*ae)^2-m^2)/(4*mu0*h/100*freq*10^9);

gt=grad+gc+gd;

Rin0=1/gt;

if option1==1

Rin=Rin0*besselj(1,k*RHOo)^2/besselj(1,k*ae)^2;

else

temp1=Zin/Rin0*besselj(1,k*ae)^2;

maxrho=ae;

minrho=0;

tempk=1;

while tempk>0.00001

nk=0;

rhox=linspace(minrho,maxrho,100);

temp=besselj(1,k.*rhox).^2;

for kk=1:99

if temp(kk)-temp1<=0

if temp(kk+1)-temp1>0

nk=nk+1;

minrho=rhox(kk);

maxrho=rhox(kk+1);

end

else

if temp(kk+1)-temp1<=0

nk=nk+1;

maxrho=rhox(kk);

minrho=rhox(kk+1);

end

end

end

if nk>1

display('*****Warning, there are more than one solutions for RHOo and this program only provides you one exact solution!*****/n');

end

[tempk,kk]=min(abs(temp-temp1));

RHOo=rhox(kk);

end

end

% Directivity

[D,DdB]=dir_cir(a,ae,ko);

% Display (circular)

clc;

if (option_a==2),

diary(filename);

end

disp(strvcat('INPUT PARAMETERS','================'));

disp(sprintf('\nRESONANT FREQUENCY (in GHz) = %4.4f',freq));

disp(sprintf('DIELECTRIC CONSTANT OF THE SUBSTRATE = %4.4f',er));

disp(sprintf('HEIGHT OF THE SUBSTRATE (in cm) = %4.4f\n',h));

disp(strvcat('OUTPUT PARAMETERS','================='));

disp(sprintf('\nPHYSICAL RADIUS OF THE PATCH (in cm) = %4.4f',a));

disp(sprintf('EFFECTIVE RADIUS OF THE PATCH (in cm) = %4.4f',ae));

disp(sprintf('E-PLANE HPBW (in degrees) = %4.4f',EHPBW));

disp(sprintf('H-PLANE HPBW (in degrees) = %4.4f',HHPBW));

disp(sprintf('DIRECTIVITY OF CIRCULAR PATCH (dimensionless) = %4.4f',D));

disp(sprintf('DIRECTIVITY OF CIRCULAR PATCH (in dB) = %4.4f\n',DdB));

fprintf('*** TM110 MODE ***\n');

fprintf('RESONANT INPUT RESISTANCE AT RHO=ae : Rin0= %4.4f ohms\n',Rin0);

if option1==1

fprintf('RESONANT INPUT RESISTANCE AT RECESSED FEED POINT (RHO=%4.4f cm) RIN= %4.4f ohms\n',RHOo, Rin);

else

fprintf('FOR DESIRED IMPENDANCE %4.4f ohms, THE FEED POINT POSITION RHOo=%4.4f cm\n\n',Zin, RHOo);

end

disp(strvcat('*** NOTE:',...

' THE E-PLANE AMPLITUDE PATTERN IS STORED IN Epl-Micr_m.dat',...

' THE H-PLANE AMPLITUDE PATTERN IS STORED IN Hpl-Micr_m.dat',...

' ========================================================='));

diary off;

% Subfunction

function [D,DdB]=dir_cir(a,ae,ko)

th=0:90; phi=0:360;

[t,p]=meshgrid(th.*pi/180,phi.*pi/180);

x=sin(t).*ko.*ae;

J0=besselj(0,x); J2=besselj(2,x);

J02P=J0-J2; J02=J0+J2;

Ucirc=(J02P.*cos(p)).^2 + (J02.*cos(t).*sin(p)).^2;

Umax=max(max(Ucirc));

Ua=Ucirc.*sin(t).*(pi./180).^2;

Prad=sum(sum(Ua));

D=4.*pi.*Umax./Prad;

DdB=10.*log10(D);

I HAVE ATTACHED CODE FOR CIRCULAR AS WELL AS RECTANGULAR ANTENNA