Design a single-section coupled line coupler with a coupling of 19.1 dB , a system impedance of $60 \Omega$, and a center frequency of 8 GHz . If the coupler is to be made in stripline (edge-coupled), with $\epsilon_r=2.2$ and $b=0.32 \mathrm{~cm}$, find the necessary strip widths and separation.