How to define figure of merit (FOM) for dual-band branch line couplers (BLC)?

I have designed a dual-band 3dB branch line coupler operating at 0.9 GHz and 3.5 GHz. It can be designed for frequency ratio (f2/f1) range from 3.5 to 8. Also I have calculated S-parameters. Can...

17 September 2015 682 2 View