
251Microwave Components
7.6.2 Double-Hole Coupler
In this coupler, two waveguides are coupled through two holes in the com-
mon broader wall. These holes are separated by
λ
g
/4. This coupler may also
be classied as Bathe-hole coupler. Its working is illustrated in Figure 7.29b.
Accordingly, when the wave travels from port 1 to port 3, it travels the same
distance due to holes X and Y and adds constructively at port 3. The frac-
tion of the wave travelling in the reverse direction, that is, the wave coming
through hole-Y, travels
λ
g
/4 more distance than that coming through hole-X.
Thus, these two waves arriving at port 4 destructively add due to ...