The next subject to tackle in our exploration of 3D EM simulations of bandpass filters is a microstrip design. The dielectric material used is Rogers RO3003G2 PTFE laminate with a thickness of 127 µm. The filter’s layer stackup is shown in Figure 1, while its 2D geometry is shown in Figure 2. The total length of the filter is 4.1 mm.
Of the various types of microstrip bandpass filters, the hairpin filter is one of the most common. Its concept is the same as parallel-coupled, half-wavelength resonator filters. The advantage of a hairpin filter over end-coupled and parallel-coupled microstrip is how little space it consumes due to the folding of the half-wavelength resonator. Also, the hairpin design is simpler compared to the other types of microwave filters. The design methodology for this filter is well established.1,2