The present invention relates to a high frequency module board device having
a high frequency transmitting and receiving circuit for modulating and demodulating
a high frequency signal. The high frequency module board device comprises a base
board (2) whose main surface is formed as a build-up surface (2a)
and a high frequency circuit part (3) formed on the build-up surface of
the base board (2) and having passive elements formed. The base board (2)
has an area (29) in which wiring is not formed in a lower layer from a fourth
wiring layer (8b). The high frequency circuit part (3) has
an upper electrode part (36) and a lower electrode part (35) in positions
corresponding to the area (29) in which the wiring is not formed. Thus,
since a capacitance (18) is provided just above the area (29) in
which the wiring is not formed, a parasitic capacity that the capacitance (18)
receives from ground patterns (14) is reduced. Accordingly, the characteristics
of the capacitance (18) can be improved.
