Design of Microstrip Antenna with Greater Bandwidth at Frequencies … · 2015-09-30 · Design of...
Transcript of Design of Microstrip Antenna with Greater Bandwidth at Frequencies … · 2015-09-30 · Design of...
Design of Microstrip Antenna with Greater Bandwidth at Frequencies
of GHz and THz
HUMBERTO CESAR CHAVES FERNANDES, TARCISIO DA SILVA BARRETO AND OTÁVIO
PAULINO LAVOR
Department of Electrical Engineering
Federal University of Rio Grande do Norte - UFRN
University Campus Lagoa Nova
BRAZIL
[email protected], [email protected], [email protected]
Abstract: - This paper presents a microstrip antenna with circular patch that operates at a frequency of
1 THz, with a circular opening in the ground plane, resulting in an increase in bandwidth. At GHz
frequencies, the circular opening in the ground plane is performed to obtain a wide pass band. Its
prototype is built and measurements are compared with simulated data. Results of loss by insertion
and radiation patterns in plans E and H are presented.
Key-Words: - Circular patch, THz, Bandwidth.
1 Introduction The structure of a conventional microstrip antenna
comprises a radiating metal patch, embedded in a
grounded dielectric substrate. As an improvement in
the switches of the microstrip antenna, various
modifications are found in the literature.
Recent strategies for increase bandwidth include
variations in ground plane size and the shape of the
connection between the feed line and the patch [1-
3], as well as the use of PBG structures (Photonic
Band Gap). The increase in bandwidth resulting
from these factors is subject to decrease the antenna
merit factor by decreasing the dielectric constant
[4].
In case these PBG structures, the dielectric
constant decreases significantly, causing a large
shift in frequency for a higher value. Thus, a change
in the ground plane becomes interesting, since it has
a simpler construction and causes a less
displacement of the frequency. At low frequencies,
the modified ground plane with curved branches
was used to improve bandwidth [5] and the
truncated plane was used in design of UWB antenna
(Ultra Wide Band) [6, 7]. The CSRR
(Complementary Split Ring Resonator) was also
used in the ground plane in antennas for UWB
applications [8]. Other modifications had been made
in the radiating element as in [9-11].
At high frequencies, microstrip antennas have
been well reported. By example, in [12], it is
presented a new supply technique using a
waveguide transformer. Other studies are described
in [13-15].
In this paper, it proposes a microstrip antenna
with circular patch designed for the frequency of 1
THz. A circular opening is made in the ground plane
in order to obtain better results for the bandwidth,
when compared to a standard antenna, namely,
without change. The analysis is also performed at
low frequencies, so that the prototype is applicable
to UWB (Ultra Wide Band) communication system
which occupies the frequency range from 3.1 to 10.6
GHz and another shows a change in bandwidth in
center frequency of 2.5 GHz.
2 Design of the Antenna In frequency of THz, for standard antenna, it
proposes a microstrip antenna with circular patch of
radius r = 24.6 µm, fed by a microstrip line of length
b= 21.9 µm and width w = 2.26 µm. The substrate is
silicon with relative permittivity (εr) of 11.9 and a
thickness of 5 µm. The material used for patch,
power line and ground plane is gold. A modification
is made making a circular opening of radius R in the
center of the ground plane. Figure 1 shows the
geometry of the antenna.
Mathematical and Computational Methods in Electrical Engineering
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Fig. 1. Geometry of the antenna. a) patch, b) ground plane.
In the case of antenna that operates at
frequencies of GHz, it is designed a antenna for the
frequency of 6.5 GHz and other for the frequency of
2.5 GHz. For the frequency of 6.5 GHz, the used
substrate is fiberglass (FR4) with relative
permittivity (εr) 4.4 and thickness 1.58mm. The
dimensions are r = 6 mm, b = 4 mm, w = 3 mm and
R = 11 mm. The material used for patch, power line
and ground plane is copper.
3 Results
Simulations were carried to obtain return loss versus
frequency, well as bandwidth. Three different values
of R are considered and S11 as function of frequency
can be seen in figure 2.
Fig. 2. Simulated S11 for standard antenna and with circular
opening at THz.
Here it can be seen that with the increase of R, there
is a frequency offset to the left, however, it also an
increase in bandwidth. While the standard antenna
has a bandwidth 67.5 GHz, antennas with circular
openings has a bandwidth of 90.5 GHz, 115.5 GHz
and 145.7 GHz for R = 10 µm, 15 µm and 20 µm,
respectively. For any value of R, a better impedance
matching is realized.
Figures 3 to 6 show the radiation patterns for these
antennas, where the angle ϕ is between 0° and 360°.
Fig. 3. Radiation pattern of the standard antenna at THz.
Fig. 4. Radiation pattern of the antenna with circular opening.
R=10µm.
Fig. 5. Radiation pattern of the antenna with circular opening. R=15µm.
Fig. 6. Radiation pattern of the antenna with circular opening.
R=10µm.
Mathematical and Computational Methods in Electrical Engineering
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In the following, experimental results of this
analysis are shown in frequencies of GHz. For the
frequency of 6.5 GHz, the picture of the antenna is
shown in Figure 7.
Fig. 7. Picture of the designed antena for 6.5 GHz.
Figure 8 shows the results for S11 versus
frequency comparing the simulated results with the
measured. In this model were obtained three
operating bands, one ranging from 2.5 to 2.9 GHz,
or 15% bandwidth with a center frequency of 2.7
GHz, another ranging from 3.7 to 7.5 GHz which
corresponds to 68% of bandwidth to the center
frequency of 5.6 GHz and another ranging from 8.8
to 10.9 GHz corresponding to 21% of the bandwidth
to the center frequency of 9.85 GHz.
Fig. 8. Measured and simulated values of S11.
For this configuration, the model constructed has
frequencies in the range of UWB, which qualifies
for applications in UWB communication systems.
Figure 10 shows the radiation pattern for this
antenna, where the angle ϕ is between 0° and 360°.
Fig. 9. Radiation pattern of the antenna with circular opening on the
ground plane.
For designed antenna for 2.5 GHz, the results are
presented below. Figure 10 shows the values of
return loss as a function of operating frequency for
the antenna pattern and proposed.
Fig. 10. Values of return loss as a function of operating frequency for
the standard and proposed antenna for 2.5 GHz.
One can observe a change in the return loss of
the antenna when using the proposed structure.
Through values it is possible to observe an
improvement in bandwidth for the proposed
configuration. The standard antenna has a return
loss of -22.41 dB and a bandwidth of 27 MHz, while
the proposed antenna has a return loss of -35.25 dB
and a bandwidth of 282 MHz.
Figures 11 and 12 show the radiation pattern of
the standard and proposed antenna for 2.5 GHz,
respectively.
Mathematical and Computational Methods in Electrical Engineering
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Fig. 11. Radiation pattern of the standard antenna.
Fig. 12. Radiation pattern of the proposed antenna.
The proposed antenna was built, since its large
increase in bandwidth. The images can be seen in
figure 13.
Fig. 13. Picture of the designed antena for 2.5 GHz.
Figure 14 shows the measured and simulated
data for the fabricated antenna where is possible
make a comparison between measured and
simulated data.
Fig. 14. Measured and simulated data of return loss for the proposed
antenna.
The graph shows a comparison of return loss for
the measured and simulated data in a range of 1 at
4.5 GHz. It is possible to see an approximation of
the measured data in relation to the simulated.
Another parameter measured is the input impedance
and can be seen in Figure 15.
Fig. 15. Input impedance of the proposed antenna.
In the resonant frequency of 2.7 GHz, the
measurement of input impedance is 49.7 – 0.6j Ω,
being a value very close to 50 Ω.
4 Conclusion A microstrip antenna with circular opening in the
ground plane was proposed and designed for
frequency of 1 THz, give a better bandwidth. The
same analysis was performed at frequencies of 6.5
and 2.5 GHz. Antenna were fabricated and
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measurements were performed, obtaining good
results. An antenna shown to be applicable to UWB
telecommunication system and the other had a
change in the bandwidth of 27 to 282 MHz in center
frequency of 2.5 GHz. New results of loss by
insertion and radiation patterns in the E and H
planes were presenteds.
References:
[1] O. M. H. Ahtmed and A.R. Sebak. “A Noval
Printed Monopole Antenna for Future Ultra
WideBand Communication Systems”,
Micriwave and Optical Technology Letters, v.
53, n°8, 2011.
[2] M. Koohestani, M. N. Moghadasi and
B.S.Virdee, “Miniature microstrip-fed ultra-
wideband printed monopole antenna with a
partial plane atructure”, IET Microwaves,
Antennas & Propagation, v. 5, pp. 1683-1689,
2011.
[3] M. Ojaroudi and A. Faramarzi,
“Multiresonance Amall Square Slot Antenna
for Ultra-WideBand Applications”, Micriwave
and Optical Technology Letters, v. 53, n°9,
2011.
[4] L. G. da Silva, Filtena:Integração de Antenas e
Filtros de RF e Microondas Reconfuguráveis,
Instituto Nacional de Telecomunicações-Inatel,
Santa Rita do Sapucaí, 2014.
[5] Y.M. Pan, S.Y. Zheng and B.J. Hu,
“Wideband and Low-Profile Omnidirectional
Circularly Polarized Patch Antenna”, IEEE
Trans. Antennas Propag, v.62, no.8, pp. 4347-
4351, 2014.
[6] H. C. C. Fernandes, M. P. Sousa Neto and C.
G. Moura. “Design of a Ultrawideband
Monopole Antenna Using Split Ring Resonator
for Notching Frequencies”, Mivrowave and
Optical Technology Letters, v. 56, pp. 1471-
1473, 2014.
[7] R. A. dos Santos, I. F. da Costa e A. Cerqueira
Júnior, “Novo Modelo de Antena Impressa com
Banda Ultralarga”. MOMAG 2014: 16º SBMO
- Simpósio Brasileiro de Micro-ondas e
Optoeletrônica e 11º CBMag - Congresso
Brasileiro de Eletromagnetismo, Curitiba,
2014.
[8] H. C. C. Fernandes, I. B. T. da Silva, H. D. de
Andrade, J. L. da Silva and J. P. P. Pereira,
Design of Microstrip Patch Antenna With
Complementary Split Ring Resonator Device
for Wideband Systems Application, Microwave
and Optical Technology Letters,
57,(2015),1326-1330.
[9] Y.M. Pan and K.W. Leung, Wideband
omnidirectional circularly polarized dielectric
resonator antenna with parasitic strips, IEEE
Trans. Antennas Propag., vol. 60, no. 6, (2012),
2992–2997.
[10] W. W. Li and K. W. Leung, Omnidirectional
circularly polarized dielectric resonator antenna
with top-loaded Alford loop for pattern
diversity design, IEEE Trans. Antennas
Propag., vol. 61, no. 2, (2013), 563–570.
[11] M.M. Sharma, S. Yadav, A. Kumar, D.
Bhatnagar, R.P. Yadav; Design of broadband
multi-layered circular microstrip antenna for
modern communication systems, Microwave
Conference Proceedings (APMC), 2010 Asia-
Pacific, (2010), 742-745.
[12] K.R. Jha and S. K. Sharma, “Waveguide
integrated Microstrip patch antenna at THz
frequency”, Antennas and Propagation Society
International Symposium (APSURSI), 2014
IEEE, pp.1851-1852, 2014.
[13] K.R. Jha and G. Singh, “Analysis of Dielectric
Permittivity and Losses of Two-layer Substrate
Materials for Microstrip Antenna at THz
Frequency”, Advances in Recent Technologies
in Communication and Computing, 2009.
ARTCom '09. International Conference on,
pp.672-675, 2009.
[14] J. Federici and L. Moeller, “Review of
terahertz and subterahertz wireless
communications”, J. Appl. Phys., v. 107, no.
11, pp. 111101, 2010.
[15] K. R. Jha and G. Singh, “Terahetz plannar
antennas for future wireless communcation: a
technical review”, Infrared Physics and
Technology,v. 60, pp. 71-80, 2013.
Mathematical and Computational Methods in Electrical Engineering
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