High pass filter

I got to know about highpass filter from G.L.Matthaei's book
<Microwave filters,Impedance matching networks and coupling structures>
In the book,a quasi-lumped-element high pass filter was designed,using parallel
short lines to realize inductors and using dielectric gaps to realize capacitors.
so the cross_section must not be square.

The high pass filters manufactured by wainwright as shown in the attached file
are very compact and have squre cross section.how was it realized?

i think this is a waveguide filter or a stripline filter using shorted stubs less than quater wave

High pass filter in general is not easy to make, however, waveguide itself is a high pass filter so it is easier in waveguide strcuture to realize a high pass.

Linda