How can i find poles and zeros of analogic filter?

Hi Guys

I need some help to find the poles and zeros of notch filter but i can not get the desire 80 dB of attenuation, do you know how can i do it?

My code is here....

N     = 7;        % Order must be even           
  F0    = 5800e6;   % Center frequency             
BW    = 5e6;      % Bandwidth                    
Ast   = 80;       % Stopband Attenuation (dB) 

[zero1,polo1,k1]= butter(N,2*pi*[F0-(BW/2)  F0+(BW/2)], 'stop', 's')
[num1,den1] = zp2tf(zero1,polo1,k1);
w= 2*pi*logspace(log10(F0/10),log10(F0*10),5000);
H1 = freqs(num1,den1,w);

%Gráfico S21 vs Freq
figure(1)
plot(w/(2*pi),20*log10(abs(H1)),'g','LineWidth',1); hold on;

[Star Strider]

You are probably not going to be able to do that with a Butterworth design. Consider a Chebyshev or FIR filter.