An active integrated antenna working in the millimeter wave has been realized in a monolithic process. The concept of active integrated antenna is first introduced, then the design of the integrated circuit based on a global approach, following electromagnetic and circuit simulations, is presented. The obtained performances of the active antenna are discussed and compared to a passive one

Drissi, M’hamed

Marzolf, Eric

English

AMS Acta - Alm@DL - Università di Bologna

GLOBAL DESIGN OF AN ACTIVE INTEGRATED ANTENNA
FOR MILLIMETER WAVE
Eric Marzolf, M’hamed Drissi
LCST/INSA de Rennes, 20 avenue des Buttes de Coësmes 35043 Rennes cedex, France
E-mail: Eric.Marzolf@insa-rennes.fr
ABSTRACT
An active integrated antenna working in the millimeter wave has been realized in a monolithic
process. The concept of active integrated antenna is first introduced, then the design of the
integrated circuit based on a global approach, following electromagnetic and circuit simulations, is
presented. The obtained performances of the active antenna are discussed and compared to a
passive one.
I. CONCEPT OF THE ACTIVE INTEGRATED ANTENNA
Active integrated antennas (AIA) consist of integrating a radiating element with active circuits
directly on the same substrate. A classification of such antenna modules which provide original
architectures for modern microwave has been presented by T. Itoh in [1], based on the associated
function. In a later review [2], the same author gives a deep insight of the benefits of the AIA
concept: interesting properties are resulting by a tightly building of the radiation function and the
signal processing.
Some recent developments show also that AIA can be applied in millimeter-wave systems [3]-[4],
and that they prove to be an interesting concept in response to critical issues which exist in this
bandwidth, as for instance losses in transmission lines or due to bulky interconnect between several
radio parts. Fabrication technology for both GaAs and Si is maturing and makes them both
attractive for AIA in the millimeter-wave band.
In this present work, we have associated an antenna to the input port of a low-noise amplifier on a
same GaAs substrate. Hence, we obtain among others a greater antenna gain performance, a larger
system bandwidth and a higher polarization purity. Also, as the antenna is considered as an integral
part of the circuit, this means that the tight coupling between the different components has to be
taken into account by an effort of a global simulation. As frequency increases, this is even more
significant, so especially in the millimeter-wave band.
II. DESIGN APPROACH
The active integrated antenna (see figure 1) is realized in a HEMT technology, the ED02AH process
from OMMIC, with a gate length of 0.2 µm and a transition frequency of 63 GHz. The antenna
consists of a circular patch fed by a simple microstrip line which connects directly to the input port
of the amplifier. This keeps the purity of the radiated polarization at its best. It results that the
radiated E plane is located in the same plane as the microstrip line. The amplifier has three transistor
stages, all are polarized at the same bias point (Vds=3V, Ids=22mA). The obtained gain by the
amplifier is of 11,2dB, its input is matched to the antenna impedance and its output to 50 Ω.
Figure 1: layout of the active integrated antenna
The circuit is designed by mean of a global approach, using a full wave analysis in the frequency
domain [5], with the assumption that the corresponding network behaves linearly. An
electromagnetic tool, based on the solving of the surface integral equations, is used to compute the
compression matrix [6] resulting from the distributed parts of the circuit. Then a circuit analysis
allows to connect the lumped elements together with the multi-port network, represented by the
computed matrix. One should pay specifically attention to the problem of segmentation between the
various parts of the circuit. Internal ports calibrated to 50 Ω impedance are used to represent the
interface with the lumped elements. External ports however, which remain calibrated to the
characteristic impedance of corresponding transmission lines, are for a junction representation
where no discontinuity appears. Finally all types of mutual coupling that exist in the circuit are
rigorously taken into account, and matching between the different stages can better be handled.
III. PERFORMANCES
For the comparison of the results, a passive antenna is designed and matched to 50 Ω as presented in
figure 2.
Figure 2: layout of the passive reference antenna
The S parameters, computed and measured are presented in figure 3. The measurements have been
performed directly on wafer by mean of a coplanar probe station. The calibration has been done
with standards realized on the same substrate. A phase shift is observed between simulation and
measure of the passive antenna. For the active one, the bias point has shown to be somewhat
different between simulation and measure. The best match has been obtained when the transistors
were set to (Vds=1,6V, Ids=22mA).
freq (55.00GHz to 65.00GHz)
S 
pa
ra
m
et
er
Passive antenna
measuresimulation
freq (55.00GHz to 65.00GHz)
S 
pa
ra
m
et
er
Active antenna
measuresimulation
Figure 3: S parameter for the passive and the active antennas
Concerning the radiation performances, figure 4 shows the gain versus frequency for both
structures. The antenna gain for the active structure is increased by the presence of the amplifier. On
the other hand, the gain of the passive antenna matched to 50 Ω is lower than the one corresponding
to the circular patch alone. It is shown also by the figure 5 that the purity of the radiated polarization
is optimal for the active structure. For the comparison, the loss of performance due to the matching
network is showed for the passive structure.
54 56 58 60 62 64 66
freq (GHz)
-5
0
5
10
15
20
G
ai
n 
(d
B)
active antennapassive antenna
Figure 4: gain versus frequency for the passive and active antennas
IV. CONCLUSION
It has been shown in this paper that in a receiver architecture the AIA concept improves the overall
system performances like antenna gain (hence signal-to-noise ratio), working bandwidth and purity
of radiated polarization over usual microstrip antennas. This makes them attractive for emerging
applications like indoor broadband communications for millimeter-wave band.
Finally, the global approach developed for the design of the active integrated antenna allows to treat
the antenna as an integral part of the structure. Its increased complexity at millimeter wave,
resulting from the various coupling, is also best modeled in this way.
REFERENCES
[1] J. LIN, T. ITOH, “Active integrated antennas”, IEEE Trans. MTT, vol. 42, pp. 2186-2194,
1994.
[2] Y. QIAN, T. ITOH, “Progress in active integrated antennas and their applications”, IEEE
Trans. MTT, vol. 46, pp. 1891-1900, 1998.
[3] E. M. BIEBL, “Millimeter wave systems based on active integrated antennas”, Antennas and
Propagation Millenium Conference, European Space Agency, Davos, 2000.
[4] Y. HIRACHI, S. KURODA, “Status of millimeter-wave MMIC’s and their applications in
Japan”, European Microwave Conference, pp. 79-82, 2000.
[5] R. GILLARD, M. DRISSI, J. CITERNE, “Full wave analysis in the frequency domain”,
Analysis and design of integrated circuit antenna modules, edited by K. C. GUPTA and P. S.
HALL, John Wiley, 2000.
[6] J. KUNISCH, M. RITTWEGER, S. HEINEN, I. WOLFF, “The compression approach : a new
technique for the analysis of distributed circuits containing nonlinear elements”, European
Microwave Conference, pp. 1296-1301, 1991.
-100 -80 -60 -40 -20 0 20 40 60 80 100
angle (degre)
-50
-40
-30
-20
-10
0
10
E_
co
 (d
B)
E plane
-100 -80 -60 -40 -20 0 20 40 60 80 100
angle (degre)
-50
-40
-30
-20
E_
cr
os
s 
(d
B)
-100 -80 -60 -40 -20 0 20 40 60 80 100
angle (degre)
-50
-45
-40
-35
-30
-25
E_
cr
os
s 
(d
B)
-100 -80 -60 -40 -20 0 20 40 60 80 100
angle (degre)
-50
-40
-30
-20
-10
0
E_
co
 (d
B)
H plane
active antennapassive antenna
Figure 5: radiated field components for the passive and active antennas


Global design of an active integrated antenna for millimeter wave

AMS Acta

GLOBAL DESIGN OF AN ACTIVE INTEGRATED ANTENNAFOR MILLIMETER WAVEEric Marzolf, M’hamed DrissiLCST/INSA de Rennes, 20 avenue des Buttes de Coësmes 35043 Rennes cedex, FranceE-mail: Eric.Marzolf@insa-rennes.frABSTRACTAn active integrated antenna working in the millimeter wave has been realized in a monolithicprocess. The concept of active integrated antenna is first introduced, then the design of theintegrated circuit based on a global approach, following electromagnetic and circuit simulations, ispresented. The obtained performances of the active antenna are discussed and compared to apassive one.I. CONCEPT OF THE ACTIVE INTEGRATED ANTENNAActive integrated antennas (AIA) consist of integrating a radiating element with active circuitsdirectly on the same substrate. A classification of such antenna modules which provide originalarchitectures for modern microwave has been presented by T. Itoh in [1], based on the associatedfunction. In a later review [2], the same author gives a deep insight of the benefits of the AIAconcept: interesting properties are resulting by a tightly building of the radiation function and thesignal processing.Some recent developments show also that AIA can be applied in millimeter-wave systems [3]-[4],and that they prove to be an interesting concept in response to critical issues which exist in thisbandwidth, as for instance losses in transmission lines or due to bulky interconnect between severalradio parts. Fabrication technology for both GaAs and Si is maturing and makes them bothattractive for AIA in the millimeter-wave band.In this present work, we have associated an antenna to the input port of a low-noise amplifier on asame GaAs substrate. Hence, we obtain among others a greater antenna gain performance, a largersystem bandwidth and a higher polarization purity. Also, as the antenna is considered as an integralpart of the circuit, this means that the tight coupling between the different components has to betaken into account by an effort of a global simulation. As frequency increases, this is even moresignificant, so especially in the millimeter-wave band.II. DESIGN APPROACHThe active integrated antenna (see figure 1) is realized in a HEMT technology, the ED02AH processfrom OMMIC, with a gate length of 0.2 µm and a transition frequency of 63 GHz. The antennaconsists of a circular patch fed by a simple microstrip line which connects directly to the input portof the amplifier. This keeps the purity of the radiated polarization at its best. It results that theradiated E plane is located in the same plane as the microstrip line. The amplifier has three transistorstages, all are polarized at the same bias point (Vds=3V, Ids=22mA). The obtained gain by theamplifier is of 11,2dB, its input is matched to the antenna impedance and its output to 50 Ω.Figure 1: layout of the active integrated antennaThe circuit is designed by mean of a global approach, using a full wave analysis in the frequencydomain [5], with the assumption that the corresponding network behaves linearly. Anelectromagnetic tool, based on the solving of the surface integral equations, is used to compute thecompression matrix [6] resulting from the distributed parts of the circuit. Then a circuit analysisallows to connect the lumped elements together with the multi-port network, represented by thecomputed matrix. One should pay specifically attention to the problem of segmentation between thevarious parts of the circuit. Internal ports calibrated to 50 Ω impedance are used to represent theinterface with the lumped elements. External ports however, which remain calibrated to thecharacteristic impedance of corresponding transmission lines, are for a junction representationwhere no discontinuity appears. Finally all types of mutual coupling that exist in the circuit arerigorously taken into account, and matching between the different stages can better be handled.III. PERFORMANCESFor the comparison of the results, a passive antenna is designed and matched to 50 Ω as presented infigure 2.Figure 2: layout of the passive reference antennaThe S parameters, computed and measured are presented in figure 3. The measurements have beenperformed directly on wafer by mean of a coplanar probe station. The calibration has been donewith standards realized on the same substrate. A phase shift is observed between simulation andmeasure of the passive antenna. For the active one, the bias point has shown to be somewhatdifferent between simulation and measure. The best match has been obtained when the transistorswere set to (Vds=1,6V, Ids=22mA).freq (55.00GHz to 65.00GHz)S parameterPassive antennameasuresimulationfreq (55.00GHz to 65.00GHz)S parameterActive antennameasuresimulationFigure 3: S parameter for the passive and the active antennasConcerning the radiation performances, figure 4 shows the gain versus frequency for bothstructures. The antenna gain for the active structure is increased by the presence of the amplifier. Onthe other hand, the gain of the passive antenna matched to 50 Ω is lower than the one correspondingto the circular patch alone. It is shown also by the figure 5 that the purity of the radiated polarizationis optimal for the active structure. For the comparison, the loss of performance due to the matchingnetwork is showed for the passive structure.54 56 58 60 62 64 66freq (GHz)-505101520Gain (dB)active antennapassive antennaFigure 4: gain versus frequency for the passive and active antennasIV. CONCLUSIONIt has been shown in this paper that in a receiver architecture the AIA concept improves the overallsystem performances like antenna gain (hence signal-to-noise ratio), working bandwidth and purityof radiated polarization over usual microstrip antennas. This makes them attractive for emergingapplications like indoor broadband communications for millimeter-wave band.Finally, the global approach developed for the design of the active integrated antenna allows to treatthe antenna as an integral part of the structure. Its increased complexity at millimeter wave,resulting from the various coupling, is also best modeled in this way.REFERENCES[1] J. LIN, T. ITOH, “Active integrated antennas”, IEEE Trans. MTT, vol. 42, pp. 2186-2194,1994.[2] Y. QIAN, T. ITOH, “Progress in active integrated antennas and their applications”, IEEETrans. MTT, vol. 46, pp. 1891-1900, 1998.[3] E. M. BIEBL, “Millimeter wave systems based on active integrated antennas”, Antennas andPropagation Millenium Conference, European Space Agency, Davos, 2000.[4] Y. HIRACHI, S. KURODA, “Status of millimeter-wave MMIC’s and their applications inJapan”, European Microwave Conference, pp. 79-82, 2000.[5] R. GILLARD, M. DRISSI, J. CITERNE, “Full wave analysis in the frequency domain”,Analysis and design of integrated circuit antenna modules, edited by K. C. GUPTA and P. S.HALL, John Wiley, 2000.[6] J. KUNISCH, M. RITTWEGER, S. HEINEN, I. WOLFF, “The compression approach : a newtechnique for the analysis of distributed circuits containing nonlinear elements”, EuropeanMicrowave Conference, pp. 1296-1301, 1991.-100 -80 -60 -40 -20 0 20 40 60 80 100angle (degre)-50-40-30-20-10010E_co (dB)E plane-100 -80 -60 -40 -20 0 20 40 60 80 100angle (degre)-50-40-30-20E_cross (dB)-100 -80 -60 -40 -20 0 20 40 60 80 100angle (degre)-50-45-40-35-30-25E_cross (dB)-100 -80 -60 -40 -20 0 20 40 60 80 100angle (degre)-50-40-30-20-100E_co (dB)H planeactive antennapassive antennaFigure 5: radiated field components for the passive and active antennas

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Global design of an active integrated antenna for millimeter wave

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