Assume you want to design a 3 GHz low pass filter and you wa…

Assume you want to design a 3 GHz low pass filter and you want the rejection at 6  GHz (so twice the normalized cut-off frequency) to be at least 20 dB. (i.e. S21 < -20 dB) Which of the following filter prototype choices  might do the job (select all that apply) 

3b.  Assume that you want to realize the matching circuit of…

3b.  Assume that you want to realize the matching circuit of question 3a on a section of microstrip line with a relative dielectric constant Er of 9.9 at a frequency of 3 GHz.  Using the approximations you may need to use, estimate the length of microstrip line that would be needed for the transformer section.