# hybrid coupler characteristic impedance

#### erumai

Joined Sep 28, 2007
4
Hi friends,

Do any one of you know why we use a 71 ohm characteristic impedance networks in a hybrid coupler to couple 50 ohms input and outputs?

#### hon

Joined Jun 22, 2006
4
You really should look up a book on transmission lines or microwave engineering book to get details. But simply, it is related to 1/4 wavelength transmission line property and matching between 50 ohm inputs.

#### John_2016

Joined Nov 23, 2016
55
figure 7.21 on page 343 shows thicker quarter wavelength sections for the 70.7 Ohm than the Z0=50 Ohm vertical sections of the hybrid. It should be the other way around.

Thicker microstrip lines tend to have lower Z0 and thinner microstrip lines tend to have higher Z0, as shown in page 143 formulas of same literature reference.

#### Wendy

Joined Mar 24, 2008
22,164
This thread is more than 10 years old. you have practiced the arcane art of necroposting which is frowned on at AAC. I would be surprised if you get any response at all on this thread, for now I have approved your post and will see what happens.

#### John_2016

Joined Nov 23, 2016
55

that perhaps admin would consider closing with the following

clear all;clc;close all
N=5e3
L=1:N;
tic
for k=1:1:numel(L)
L2{k}=[1:L(k)];
end
prime_list=[]
for k=1:1:N
if nnz(mod(k*ones(1,numel(L2{k})),L2{k}))==k-2
prime_list=[prime_list k];
end
end
toc
Elapsed time is 0.213874 seconds.

Also, a way to collect the result in text format:

prime_list_char=num2str(prime_list)
file_id=fopen('prime_list.txt','w');
fprintf(file_id,'Primes below %s :\n\n',num2str(N));
fprintf(file_id,'%s',prime_list_char);
fclose(file_id)