Monolitic and Hybrid Approaches
PhD Thesis, Uppsala University,
Oct. 2006, 69 pp. summary, Acta Universitas Upsaliensis 221.
Dissertation in Engineering Science with specialization
in Microwave Engineering, publicly examined
in Siegbahnsalen, Ångström Laboratory,
Uppsala on October 12, 2006 at 10.15 a.m.
The thesis available in
Paper copies of the thesis can be obtained from
Signals and Systems Group, Uppsala University,
Box 534, SE-75121 Uppsala, Sweden.
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Due to recent advances in semiconductor manufacturing, complete single
chip radio receivers and transmitters for micro- and millimeterwave
frequencies can be built in standard silicon processes. However, an
external antenna has so far been needed in order to obtain a complete
radio module. In this thesis, integration of antennas on the same chip
or printed circuit board as the radio electronics is presented.
The use of on-chip antennas offers the benefit of reduced complexity in
the packaging and assembly of millimeter-wave radio modules. The absence
of an external antenna also allows complete wireless communication and
sensor modules of only a few millimeters size to be built. One
application for the studied integrated antenna radio chips is short
range communication links operating in the license exempt 24 GHz and 60
GHz frequency bands. Another application is car radars for collision
avoidance and intelligent cruise control at 24 GHz and 77 GHz.
It is known that the capacity and range of wireless communication
networks can be extended by the use of steerable base station antennas,
which direct the radiation towards active users in the network. Due to
the high complexity and cost, steerable antennas are however not in
common use. In this thesis, a integration method where the beam steering
electronics is placed on the same printed circuit board as the antenna
elements is proposed and evaluated. As only a few extra components are
required compared to a conventional antenna design, the additional cost
of the beam steering electronics is low.
This thesis considers integration of antennas and
active electronics manufactured on the same
substrate. The main topic is on-chip antennas for
commercial silicon processes, but hybrid integration
using printed circuit board technology is also
The possible use of micromachining techniques as a
means of reducing substrate losses of antennas
manufactured on low resistivity silicon wafers is
investigated. Compact dipole, loop, and inverted-F
antennas for the 20-40 GHz frequency range are
designed, implemented, and characterized. The
results show significantly improved antenna
efficiency when micromachining is used as a
post-processing step for on-chip antennas
manufactured in silicon technology.
High resistivity wafers are used in a commercial
silicon germanium technology to improve the
efficiency of dipole antennas realized using the
available circuit metal layers in the process.
Monolithically integrated 24 GHz receivers with
on-chip antennas are designed and evaluated with
regard to antenna and system performance. No
noticeable degradation of the receiver performance
caused by cross talk between the antenna and the
integrated circuit is observed.
For low frequency antenna arrays, such as base
station antennas, hybrid integration of active devices
within the antenna aperture is treated. A compact
varactor based phase shifter for traveling wave
antenna applications is proposed and evaluated.
Electrically steerable traveling wave patch antenna
arrays, with the phase shifters implemented in the
same conductor layer as the radiating elements, are
designed and manufactured in microstrip
technology. It is experimentally verified that the
radiation from the feed network and phase shifters in
the proposed antenna configuration is small.
antenna travelling wave arrays, antenna phased
arrays, phase shifters, micromachining, silicon,
monolithic microwave integrated circuits, dipole
antennas, loop antennas, slot antennas.