  In this paper, first, we review a straightforward analytical technique based
on image impedance concept for designing traditional microwave microstrip
coupled line filters using distributed elements. In the introduced approach, we
characterize a quarter-wave coupled line section, and then these discrete
sections can be connected in series to synthesis the final desired frequency
response. Next, we use a novel open-stub based technique to suppress spurious
harmonic frequencies. Finally, using proposed technique, we design and simulate
a band pass filter (BPF). The simulation results prove the usefulness of the
proposed technique.
