Micromachined Antennas for
Integration with Silicon Based Active Devices
Licentiate Thesis, Signals and Systems,
Uppsala University, April 2004.
Licentiate Seminar Friday, April 2, at 10:15,
room K23 at Magistern, floor -2,
Dag Hammarskjölds väg 31, Uppsala
In this thesis micromachined antennas suitable for on-chip integration
with silicon based active devices are treated. The emphasis is put on
compact 24 GHz antennas, capable of being integrated in commercial
Silicon Germanium (SiGe) processes using
low temperature post processing
Antenna types covered are the slot loop antenna, wire loop antenna,
meandered dipole and the inverted F antenna. The antennas have been
implemented on surface and bulk micromachined low resistivity silicon
substrates. It is found that the bulk micromachining method yields
antennas with improved efficiency compared
to antennas relying on thick
dielectrics for reduction of substrate losses.
Two patch antennas, suitable for wafer level integration with active
devices are covered. A 60 GHz micromachined aperture coupled patch
antenna with a bandwidth of 59-64 GHz is presented. A novel 24 GHz
differentially fed patch antenna, manufactured using a thick organic
dielectric, is modeled with a modified transmission line method.
Low Temperature Co-fired Ceramic (LTCC)
and glob-top packaging for
integrated antennas is evaluated. Epoxy based glob tops are found to
have lower losses than silicone based ones.
Finally, cross talk for simple on-chip wire interconnects is analyzed
for integrated slot antennas manufactured in SiGe processes. It is shown
that by proper connection of the antenna to the semiconductor substrate
a high degree of isolation can be obtained.