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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 67, NO. 4, APRIL 2019
Highly Efficient, Wideband Microstrip Patch
Antenna With Recessed Ground at 60 GHz
Anushruti Jaiswal, Student Member, IEEE, Mahesh P. Abegaonkar , Senior Member, IEEE,
and Shiban Kishen Koul , Fellow, IEEE
Abstract— The effects of finite air-filled recessed ground on
the reflection and radiation characteristics of a microstrip patch
antenna at 60 GHz are investigated. The recessed ground patch
antenna is analyzed using a 2-D capacitance model to understand
the effect of the dimensions of the recessed ground plane on the
effective dielectric constant. A detailed parametric study of the
dimensions of the recessed ground plane is carried out to optimize
the performance of the patch antenna at 60 GHz. Prototypes of
a conventional and optimized recessed ground patch antenna at
60 GHz are fabricated on alumina ceramic substrate of height
0.127 mm with εr = 9.8. The measured results indicate that with
the recessed ground plane, an enhancement in −10 dB impedance
bandwidth by 9.48% (58.2–65 GHz) and in radiation efficiency
by 24.97% over conventional patch antenna can be achieved at
60.1 GHz. A gain enhancement of 2.64 dB is achieved with the
recessed ground plane in the measurements. A good agreement
between theoretical and measured results confirms the advantage
of using the recessed ground plane.
Index Terms— 60 GHz, microstrip patch antenna, radiation
efficiency, recessed ground, wheeler cap method, wide-band
antenna.
I. I NTRODUCTION
HE V-band spectrum around 60 GHz from 57 to 66
GHz is attractive for licence exempt broadband services.
It offers a massive capacity compared to existing unlicensed
broadband spectrum. This band is preferred for short distance
and indoor wireless communication [1]. High atmospheric
oxygen attenuation of 10–15 dB/Km makes this frequency
span limited for short distance communications. Therefore,
high radiation efficiency and wide bandwidth antennas are
desirable in this frequency range [2]. There are various existing
techniques to improve the bandwidth and efficiency of the
antenna at 60 GHz, reported in the literature. Micromachining [3] is one of the traditional methodologies. It is introduced
in foam [4], silicon-based aperture coupled and microstripfed patch antenna [5]. In [6], a dielectric resonator antenna
is presented by using micromachining in a silicon substrate.
A micromachined air-filled slot antenna is developed by
bonding three gold-plated silicon layers [7]. Cavity backing
using substrate-integrated waveguide (SIW) technique is also
T
Manuscript received July 26, 2018; revised January 5, 2019; accepted
January 8, 2019. Date of publication January 23, 2019; date of current version
April 5, 2019. (Corresponding author: Mahesh P. Abegaonkar.)
The authors are with the Centre for Applied Research in Electronics,
IIT Delhi, New Delhi 110016, India (e-mail: anushruti88jaiswal@gmail.com;
mpjosh@care.iitd.ac.in; shiban_koul@hotmail.com).
Color versions of one or more of the figures in this paper are available
online at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TAP.2019.2894319
a popular method. It is employed in T shape planar slot [8] and
rectangular slot [9] patch antenna. Air-filled metallic cavity is
one more method used in [10] to design a fully packaged
wide bandwidth patch antenna at 60 GHz using fused silica
as the superstrate. The use of micromachining and SIW-based
cavities is limited due to their time-consuming fabrication procedure and complex multilayer structures, resulting in higher
fabrication cost. However, the recessed ground technique (also
called air-filled metallic cavity) is much simpler to design and
has a lower fabrication cost. Hence, this method is chosen over
others to represent the proposed work.
A lot of other research works are also published on metallic
cavity backed patch antenna handling various issues such as
understanding the effects of the height of air gap on resonance
frequency [11] and input impedance [12] at 2 GHz. Yet,
no significant work has focused on the effects of different
parameters of recessed ground on the reflection and radiation
characteristics of the patch antenna and its related theoretical
analysis at 60 GHz.
In this paper, a quasi-static capacitance model of recessed
ground patch antenna is used to predict the reduction in effective dielectric constant of the overall structure. A series of fullwave simulations (using HFSS) is done by varying different
parameters of recessed ground of the patch antenna. Characteristics of the patch antenna including resonance frequency,
bandwidth, efficiency, and gain are studied. Multiple antennas
with different recessed ground parameters are developed and
tested to check the validity of the concept. Furthermore,
the recessed ground parameters of the patch antenna are
optimized to obtain higher bandwidth and improved efficiency
in comparison to conventional patch antenna at 60 GHz.
In contrast to other works reported, compared in Table I, this
paper has achieved a maximum measured fractional bandwidth
and efficiency. The efficiency of the antenna is measured
using the wheeler’s cap method. This paper is divided into
four sections. Section II presents the design of the proposed
antenna. Section III illustrates the effects of recessed ground
parameters on the performance of antenna and Section IV
details the fabrication and measurement results.
II. A NTENNA D ESIGN
The geometry of the proposed design is shown in Fig. 1.
It consists of a microstrip inset fed rectangular patch, substrate,
and a recessed ground. The patch dimensions L × W are
optimized to 0.745 mm × 1.1 mm to resonate at 60 GHz
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JAISWAL et al.: HIGHLY EFFICIENT, WIDEBAND MICROSTRIP PATCH ANTENNA
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TABLE I
C OMPARISON OF P ROPOSED W ORK W ITH R EPORTED W ORK
Fig. 1.
Top and side view of recessed ground patch antenna.
with the conventional ground plane on a 0.127 mm (tsub )
thick alumina ceramic with the relative permittivity of 9.8.
The dimensions of air-filled recessed ground include length b,
width a, and depth tair . It extends beyond the size of the patch
with one of its width edge fixed and aligned parallel to the
radiating edge of the patch, along which it is fed. It controls
the reflection and radiation characteristics of the patch antenna.
The size of the patch does not alter with a change in recessed
ground parameters. The inset length i l changes when the size
of the recessed ground is changed. It is optimized to 50 point according to the change in input impedance. The total
height of mixed air substrate is t = tair + tsub . The overall
size of the ground plane is l g × wg .
III. E FFECTS OF R ECESS G ROUND PARAMETERS ON
P ERFORMANCE OF PATCH A NTENNA
A. Reduction in Effective Dielectric Constant
Fig. 2 shows a quasi-static capacitance model based
on series capacitance between patch and recessed ground.
Fig. 2(a) describes the case when only the depth of the
recessed ground is varied whereas the length and width are
kept equal to the size of the patch. Total capacitance C
is a combination of fringing capacitance, c f and mixed
air-substrate region capacitance, cm and is, calculated as
C = εe f f · A/t = c f + cm + c f .
(1.1)
Fig. 2. Capacitance model of recessed ground patch antenna (a) when b = L,
(b) when b is extended beyond the physical length of patch antenna along
one side, and (c) both sides symmetrically.
Effective dielectric constant (εef f ) of the overall structure is
estimated by the following expression:
ε f · L
1
(1.2)
+ εm · L
εe f f =
2
2L + L
1− xf
εm = (εsub · εair )/(x air (εsub − εair ) + εair ) (1.3)
where x f = x air = (tair /t) in fringing and mixed fields
region, respectively.
In the above-mentioned equations, relative dielectric constant in fringing region, ε f and extended electrical length,
L are determined from [13]. Permittivity ε f is used for
calculation of L. Due to the absence of recessed ground in
fringing region, x f = 0. Relative dielectric constant in mixed
region, εm is calculated from (1.3), reduces exponentially with
increase in tair and saturates after tair ≥ tsub . It reduces to
value 2 at tair = tsub .
The reduction in εe f f using (1.2) is illustrated as case a
in Fig. 3. It reduces sharply from 9.8 to 3.45 at tair = tsub
and then increases subsequently. The gradual increase is due
to the saturation in εm and linear increase in the value of L
in (1.2). Fig. 2(b) demonstrates the case when the length of
the recessed ground is extended along one side only, whereas
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Fig. 3.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 67, NO. 4, APRIL 2019
Effective dielectric constant of overall structure as a function tair .
Fig. 4.
Comparison of extended electrical length as a function tair .
in Fig. 2(c), it is extended along both sides symmetrically.
εe f f is derived for both the cases. Total capacitance is
C = c f 1 + cm + c f 2 .
For case b
εe f f
ε f · L 1
+ εm · L + ε f 2 · L 2
1 − xf1
(1.5)
= (ε f · εair )/(x f 2 · (ε f − εair ) + εair )
1
=
L 1 + L + L 2
εf1 = εf , εf2
(1.4)
(1.6)
x f 2 = x air and x f 1 = x f = 0.
(1.7)
Fig. 5. Variation of effective dielectric constant with increase in a and tair
at b = L.
For case c
1
[εm · L + 2(ε f 2 · L 1 )]
2.L 1 + L
= ε f 2 and x f 1 = x f 2 = x air .
εe f f =
εf1
(1.8)
(1.9)
In case b, only radiating edge 2 of patch (i.e., along L 2 )
is in mixed air-substrate region, and therefore, due to more
fringing along this edge, ε f 2 is smaller than ε f 1 and L 2
is larger than L 1 . This can be seen in Fig. 4. In case c,
both the radiating edges of patch are in mixed air-substrate
region, and will lead to equal fringing along both the edges
with L 1 = L 2 and ε f 1 = ε f 2 . The variation in εe f f for
both the cases is compared in Fig. 3. It is observed that the
value of εe f f reduces with increase in tair and is much smaller
for case c than case b. The minimum value achieved is 1.43 at
tair = 381 μm (3tsub ). It can also be concluded that the εe f f
reduces more when the length of recessed ground is extended
beyond the physical length of the patch antenna and includes
the fringing fields in mixed air-substrate region.
The increase in the width of recessed ground enhances the
fringing from edges separated by the width of the patch. However, since they are the nonradiating edges of the patch, fields
cancel. Therefore, the capacitance model does not change with
the increase in width.
In addition, the change in εe f f is also analyzed by the
transmission line model of recessed ground patch antenna
with width (a) as a variable. A transmission line of size
equal to the patch antenna with varying a (extends both sides
symmetrically) at several values of tair is simulated in HFSS at
solution frequency of 60 GHz. The length of recessed ground
Fig. 6.
Variation of resonance frequency with increase in b and tair ;
a = 3132 μm.
b is kept constant to L. Fig. 5 shows the reduction in εe f f from
5.5 to 2.2 with the increase in a for tair = 120 μm (≈tsub ) and
remains constant for tair > 120 μm. It reduces initially along
a due to increase in the electromagnetic volume of air [14]
and then saturates due to no further change in capacitance.
B. Resonance Frequency
The change in resonance frequency ( f 0 ) of the patch
antenna by varying the recessed ground parameters [length (b),
width (a), and depth (tair )] is illustrated in Figs. 6 and 7, and
the significant observations are briefly described here. For all
values of b ≥ 1253 μm (Fig. 6) and a (Fig. 7), f 0 increases
with increase in tair initially (until tair ≤ 31.75 μm), and
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JAISWAL et al.: HIGHLY EFFICIENT, WIDEBAND MICROSTRIP PATCH ANTENNA
Fig. 7.
Variation of resonance frequency with increase in a and tair ;
b = 2269 μm.
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Fig. 9.
Variation in fractional bandwidth with increase in a and tair ;
b = 2269 μm.
TABLE II
C OMPARISON OF F RACTIONAL BANDWIDTH B ETWEEN R ECESSED
G ROUND AND C ONVENTIONAL PATCH A NTENNA
Fig. 8.
Variation in fractional bandwidth with increase in b and tair ;
a = 2624 μm.
then starts decreasing (for tair > 31.75 μm). However, for
b < 1253 μm, the f 0 increases up till tair ≤ 15.87 μm as
highlighted in Fig. 6. In addition, f 0 increases with an increase
in b along one edge [as shown in Fig. 2(b)], at all the values
of tair .
Furthermore, f 0 continually increases with increase in a
for tair ≤ 120 μm as highlighted in Fig. 7. However, for
tair > 120 μm, f 0 increases initially and then decreases with
an increase in a. This range of tair until when f 0 increases
with a is dependent on b. As εe f f reduces with increase in b,
the range of tair increases. The variation in f 0 observed in all
the cases, can be justified by the predicted trend of εe f f , with
all the dimensions of recessed ground.
C. Bandwidth
Figs. 8 and 9 shows the variation in fractional bandwidth
with increase in b and a for different values of tair at a =
2624 μm and b = 2269 μm (equal extension of 1524 μm
beyond W and L), respectively. The bandwidth enhances
with an increase in the volume of recessed ground [14] and,
henceforth, it increases with its corresponding parameters.
Regardless of equal extension of a and b (Figs. 8 and 9),
the bandwidth increases more with b than a. It is because
of significant fringing along the length of recessed ground
than width. Maximum of 9.5% and 13.5% of bandwidth is
realized at b = 2269 μm (Fig. 8) and a = 3132 μm (Fig. 9)
at tair = 381 μm. An equal increase in the bandwidth is
observed when a is extended twice that of b. For example,
approximately 7% bandwidth is achieved at a = 2116 μm
(for b = 2269 μm) and b = 1253 μm (for a = 3132 μm) for
tair = 381 μm.
In addition, the improvement in bandwidth of air-filled
recessed ground patch is compared with conventional patch
antenna for substrate thickness (tsub ) = t, given in Table II.
tsub of conventional patch antenna is varied as t. The lateral
dimensions of air-filled recessed ground patch antenna while
varying tair are kept constant as a = 3132 μm and b =
2269 μm. In Table II, it can be noted that the bandwidth
enhancement is more for air-filled recessed ground patch
antenna than the conventional patch antenna at any value of t.
A maximum of 4.92% of additional bandwidth is attained
using recessed ground at t = 508 μm. This signifies the
additional advantage of using recessed ground below patch
antenna.
D. Efficiency and Gain
Fig. 10 shows the variation in efficiency with an increase
in a for different values tair (at constant b = 2269 μm).
The efficiency increases linearly with tair for a ≥ 1608 μm.
However, for a < 1608 μm as highlighted, it increases
until tair < 31.75 μm and then it reduces further. The
efficiency also increases with increase in a, at all the values
of tair . An analogs behavior is observed with the change in
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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 67, NO. 4, APRIL 2019
TABLE III
C OMPARISON OF S IMULATED AND M EASURED R ESULTS OF R ECESSED
G ROUND PATCH A NTENNA VARYING tair , K EEPING a = W
AND b = L AS C ONSTANTS
Fig. 10.
Variation in efficiency with increase in a and tair ; b = 2269 μm.
Fig. 11. (a) Top view of through slot and plain brass ground. (b) Fabricated
image of recessed ground patch antenna with a = 3132 μm, b = 3031 μm,
and tair = 250 μm. (c) Fabricated image of conventional patch antenna.
parameter b also. The increase in the efficiency is approximately the same for equal extension along a and b.
In addition, the antenna gain follows the same trend as
efficiency. Both the parameters are improved due to fringing
fields and reduced losses in antenna because of the presence
of recessed ground. The efficiency of antenna is improved
by 31% (from 67% to 98%) and gain by 1.67 dB (from
4.95 to 6.62 dB) at b = 2269 μm, a = 3132 μm at
tair = 381 μm.
IV. FABRICATION AND M EASUREMENT
A 0.127 mm thick alumina substrate with εr = 9.8 is
used to verify the above-mentioned results. It is coated with
3 μm of gold on one side. The fabrication of antenna is
done using Maskless lithography. Laser machining is used to
create through slots in brass sheets. The slotted brass sheet
is attached with another plain brass sheet using silver solder
wire and this together forms a recessed ground. Fig. 11(a)
shows the top view of the through slot and plain brass sheet.
Finally, the printed substrate is glued with the recessed ground
using silver conductive paint, shown in Fig. 11(b). The effect
of recessed ground on resonance frequency and fractional
bandwidth of the patch antenna is verified. Three sets of four
antennas are fabricated with different dimensions of depth,
length, and width of recessed ground. While varying one
parameter, the other two are kept as constants. For illustration,
a photograph of a fabricated recessed ground patch antenna is
shown in Fig. 11(b). The extended ground plane is used to
screw the end-launch connectors (it is difficult to make holes
in 0.127 mm ceramic substrate). Southwest made 67 GHz end
launch connectors are used for antenna measurements.
TABLE IV
C OMPARISON OF S IMULATED AND M EASURED R ESULTS OF R ECESSED
G ROUND PATCH A NTENNA VARYING b, K EEPING a = 3132 μm
AND tair = 250 μm AS C ONSTANTS
TABLE V
C OMPARISON OF S IMULATED AND M EASURED R ESULTS OF R ECESSED
G ROUND PATCH A NTENNA VARYING A , K EEPING b = 2269 μm
AND tair = 250 μm AS C ONSTANTS
Comparison of simulated and measured results of three
sets of antennas with varying tair , a, and b are tabulated
in Tables III–V, respectively. In Tables III–V, it can be
estimated that the measured response agrees well with the
simulated results. The percentage error between simulated and
measured resonance frequency is higher in Table III compared
to Tables IV and V. A maximum error of 3.6% is found
at tair = 381 μm in Table III and can be accounted to
undesirable residue of silver conductive paint below the slot
due to relatively small lateral dimensions of recessed ground.
Thus, it makes the resonance frequency to offset. The agreement between simulated and measured results validates the
capacitance and transmission line model analogy of recessed
ground patch antenna.
Based on the theoretical and parametric analysis in
Section III, the recessed ground dimensions are optimized
with a = 3132 μm, b = 3031 μm, and tair = 250 μm
to obtain a high bandwidth and improved efficiency patch
antenna at 60 GHz. The performance of recessed ground patch
antenna is compared to conventional patch antenna at 60 GHz.
The photograph of a fabricated conventional patch antenna
is shown in Fig. 11(c), and whereas recessed ground patch
antenna is shown in Fig. 11(b).
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JAISWAL et al.: HIGHLY EFFICIENT, WIDEBAND MICROSTRIP PATCH ANTENNA
Fig. 12.
antenna.
Simulated return loss of conventional and recessed ground patch
Fig. 13.
antenna.
Measured return loss of conventional and recessed ground patch
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Fig. 15. Normalized gain radiation pattern of conventional patch antenna at
60 GHz. (a) E-plane and (b) H-plane. Black solid line: simulated. Red solid
line: measured.
Fig. 14. Radiation pattern measurement set up where the AUT is in receiving
mode [15].
Figs. 12 and 13 show a comparison of simulated and
measured return loss of both the antennas, respectively. The
simulated return loss result of conventional patch antenna with
extended ground is also included in Fig. 12 to prove that the
bandwidth enhancement is purely due to the recessed ground.
The measurement results of both the antennas matches well
with their simulated results. Measured reflection coefficient
of −30 and −40 dB with fractional bandwidth 1.83% and
11.3% are obtained with conventional and recessed ground
patch antenna at 60.1 GHz, respectively.
A shift of 100 MHz in resonance frequency is may be due to
the thickness of silver conductive paste between brass sheet
and substrate. An improvement in the fractional bandwidth
of 9.47% from 58.2 to 65 GHz is achieved over conventional patch antenna at 60 GHz. The accomplished fractional
bandwidth is sufficient to justify the use of recessed ground
at 60 GHz.
The radiation patterns of antenna were measured in compact
antenna test range anechoic chamber (by MI technology) using
the measurement setup shown in Fig. 14. Here, the horn
Fig. 16. Simulated and measured normalized radiation pattern in the E-plane
at (a) 58.2 GHz, (b) 60 GHz, (c) 62 GHz, and (d) 65 GHz. Black solid
line: simulated. Red solid line: measured.
antenna is used as reference transmitting antenna, located
at the focal point of the reflector to generate a plane wave
toward the antenna under test (AUT) [15]. The radiation
pattern of antennas is measured in the E-plane and H-plane.
The normalized gain radiation pattern of conventional patch
antenna at 60 GHz is shown in Fig. 15. Correlation between
the simulated and measured results is found to be good with
3 dB beamwidth of 67° and 40.5° in the E-plane and H-plane,
respectively.
The normalized E-and H-plane gain radiation patterns of
recessed ground patch antenna at 58.2, 60, 62, and 65 GHz
are shown in Figs. 16 and 17. A generally good agreement
between simulated and measured results is found. A measured
3 dB beamwidth of 55° and 80° is observed in the H-plane
and E-plane of recessed ground patch antenna at 60 GHz.
In addition, the cross polarization of the antenna in the E-plane
and H-plane is better than −15 dB at 60 GHz.
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2286
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 67, NO. 4, APRIL 2019
Fig. 19. (a) Wheeler caps of different heights with conducting ground plane
on leftmost. (b) Top view of antenna and wheeler cap. (c) Side view of antenna
enclosed in wheeler cap.
Fig. 17. Simulated and measured normalized radiation pattern in the H-plane
at (a) 58.2 GHz, (b) 60 GHz, (c) 62 GHz, and (d) 65 GHz. Black solid
line: simulated. Red solid line: measured.
Fig. 20. Measurements of conventional and recessed ground patch antenna
input reflection coefficient s11 with four different caps.
Fig. 18.
Simulated and measured gain of recessed ground patch antenna.
The antenna gain was measured using the comparative
method that involves measuring the signals received by the
reference horn antenna and by the (AUT). The relative difference in the gain of both antennas is determined. The measured
loss due to waveguide to coax adaptor is 1–1.3 dB over the
frequency range of 58–66 GHz.
This loss was taken into account in the gain measurement.
Fig. 18 shows the simulated and measured gain of the recessed
ground patch antenna across the attained bandwidth. A maximum gain of 6.94 dBi is obtained at 60 GHz. A minimum
of 5.8 dBi gain is achieved throughout the bandwidth. The
maximum discrepancy between simulation and measurement
results is about 0.8 dB. The measured gain of conventional
patch antenna is 4.3 dBi at 60 GHz.
Using recessed ground, the gain of microstrip patch antenna
is enhanced by 2.64 dBi at 60 GHz.
The radiation efficiency is an important measure for
millimeter-wave antennas. Wheeler introduced the radian cap
method, which is widely used for determining the efficiency
of the antenna [16]. This method is accurate to measure the
efficiency of electrically small antennas. A modified version of
the Wheeler method is discussed in [17] and the same method
is employed to measure the efficiency of a conventional and a
recessed ground patch antenna at 60 GHz, in this paper also.
In our work, four aluminum-based cylindrical shaped caps
of different sizes are used for enclosing the antenna. The height
of the cap is kept along the broadside radiation direction of
the antenna and it varies from λ0 /2 to 4λ0 /5. Fig. 19 displays different caps with ground plane along with efficiency
measurement setup. The steps to measure the efficiency are
elaborated in [17] and are calculated as:
ηant =
(Smax
)−1
1
2
.
−1
+ (Smin ) 1 − |S11,fs |2
(2.0)
Fig. 20 shows the measurement of conventional and recessed
ground antenna input reflection coefficient in free space and
with four metallic boxes at 60 GHz. Parameters Smax 1 ,
Smax 2 , Smin 1 and Smin 2 can be found as maximum
and minimum distance to the respective curve-fitted circles
from the free space point (S11,fs ) on the smith chart. Then,
the efficiency can be calculated using (2.0). The simulated
and measured efficiency of the conventional patch antenna is
67% and 64%, whereas for recessed ground patch, it is 98%
and 87.44%, respectively. Fig. 21 shows the comparison of
the simulated and measured efficiency across the band from
58.2 to 65 GHz. More than 81% of efficiency is obtained
throughout the band.
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JAISWAL et al.: HIGHLY EFFICIENT, WIDEBAND MICROSTRIP PATCH ANTENNA
Fig. 21. Comparison between simulated and measured efficiency of recessed
ground patch antenna.
V. C ONCLUSION
A recessed ground plane microstrip antenna with enhanced
bandwidth and efficiency is presented. The effects of different
parameters of recessed ground on the reflection and radiation
characteristics of the patch antenna are investigated through
full-wave simulations and a quasi-static capacitance model.
These are further verified through fabrication and measurements. The optimized dimensions of the recessed ground
provide a bandwidth enhancement of ≈9.5% and efficiency
enhancement of 24.97% for the patch antenna at 60 GHz.
The gain of the antenna also shows an improvement of
around 2.64 dB with recessed ground plane. This antenna
with improved bandwidth, efficiency, and gain will be useful
in wireless applications at 60 GHz. The antenna is easy to
fabricate and implement.
2287
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vol. 47, no. 8, pp. 1325–1331, Aug. 1959.
[17] R. H. Johnston and J. G. McRory, “An improved small antenna radiationefficiency measurement method,” IEEE Antennas Propag. Mag., vol. 40,
no. 5, pp. 40–48, Oct. 1998.
ACKNOWLEDGMENT
The authors would like to thank NPMASS for setting up the
state-of-the-art characterization facility at C.A.R.E, IIT Delhi
and supporting the RF MEMS research. They would also like
to thank Prof. D. Kalyanasundaram, Center for Biomedical
Engineering, IIT Delhi and NRF, IIT Delhi for allowing them
to access the fabrication facilities. They would also like to
thank Prof. Ke Wu for providing the radiation pattern measurement facility at the Poly-Grames Lab, Montreal, Canada.
Anushruti Jaiswal (S’14) received the master’s
degree in communication engineering from the Vellore Institute of Technology, Vellore, India, in 2013.
She is currently pursuing the Ph.D. degree with
the Centre for Applied Research in Electronics, IIT
Delhi, New Delhi, India.
Her current research interests include recessed
ground antennas, transmission lines, MEMS-based
polarization, frequency reconfigurable antennas, and
high gain antenna at millimeter-wave frequencies.
R EFERENCES
[1] P. Smulders, “Exploiting the 60 GHz band for local wireless multimedia
access: Prospects and future directions,” IEEE Commun. Mag., vol. 40,
no. 1, pp. 140–147, Jan. 2002.
[2] R. Zhou, D. Liu, and H. Xin, “A wideband circularly polarized patch
antenna for 60 GHz wireless communications,” Wireless Eng. Technol.,
vol. 3, no. 3, pp. 97–105, Jul. 2012.
[3] I. Papapolymerou, R. F. Drayton, and L. P. B. Katehi, “Micromachined patch antennas,” IEEE Trans. Antennas Propag., vol. 46, no. 2,
pp. 275–283, Feb. 1998.
[4] N. Caillet et al., “Foam micromachined aperture-coupled antennas for
V-band low-cost applications,” in Proc. Eur. Conf. Wireless Technol.,
Munich, Germany, Oct. 2007, pp. 308–311.
[5] A. V. López, J. Papapolymerou, A. Akiba, K. Ikeda, S. Mitarai,
and G. Ponchak, “60 GHz micromachined patch antenna for wireless
applications,” in Proc. IEEE Int. Symp. Antennas Propag. (APSURSI),
Spokane, WA, USA, Jul. 2011, pp. 515–518.
[6] M. O. Sallam et al., “Micromachined on-chip dielectric resonator
antenna operating at 60 GHz,” IEEE Trans. Antennas Propag., vol. 63,
no. 8, pp. 3410–3416, Aug. 2015.
Mahesh P. Abegaonkar (M’08–SM’13) received
the Ph.D. degree in physics (microwaves) from the
University of Pune, Pune, India, in 2002.
From 2002 to 2005, he was a Post-Doctoral
Researcher and an Assistant Professor with Kyungpook National University, Daegu, South Korea. He is
currently an Associate Professor with the Centre for
Applied Research in Electronics, IIT Delhi, New
Delhi, India. His current research interests include
microwave and millimeter-wave antennas, electromagnetic bandgap and defected ground structures,
microwave metamaterial, and reconfigurable microstrip circuits.
Dr. Abegaonkar is currently the Secretary and the Treasurer of the IEEE
MTT-S Chapter Delhi Section.
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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 67, NO. 4, APRIL 2019
Shiban Kishen Koul (S’81–M’83–SM’91–F’10)
received the B.E. degree in electrical engineering
from the Regional Engineering College, Srinagar,
India, in 1977, and the M.Tech. and Ph.D. degrees in
microwave engineering from IIT Delhi, New Delhi,
India, in 1979 and 1983, respectively.
From 2012 to 2016, he was a Deputy Director
(strategy and planning) of IIT Delhi. He is currently
a Dr. R. P. Shenoy Astra Microwave Chair Professor
with the Centre for Applied Research in Electronics,
New Delhi, where he is involved in teaching and
research activities. He is also a Deputy Director (strategy and planning,
international affairs, and research and development) of IIT Jammu, Jammu,
India. He is also the Chairman of M/S Astra Microwave Pvt. Ltd., Bengaluru,
India. He has completed 34 major sponsored projects, 52 consultancy projects,
and 57 technology development projects. He has authored or co-authored
over 400 Research Papers, 8 state-of-the art books, and 3 book chapters.
He holds ten patents and six copyrights. His current research interests include
RF MEMS, high-frequency wireless communication, microwave engineering,
microwave passive and active circuits, device modeling, millimeter-wave IC
design, and reconfigurable microwave circuits including antennas.
Dr. Koul is a fellow of the Indian National Academy of Engineering
and the Institution of Electronics and Telecommunication Engineers. He has
delivered more than 266 invited technical talks at various international
symposia and workshops. He is currently a MTT-S ADCOM Member and
a Member of IEEE MTT society’s Technical committees on Microwave
and Millimetre Wave Integrated Circuits and RF MEMS, a member of India
Initiative Team of IEEE MTT-S, a Membership Services Regional
Co-Coordinator Region-10, a Member Sight Adhoc Committee MTT-S, and
a MTT-S Speaker Bureau Lecturer. He was a recipient of the Gold Medal
by the Institution of Electrical and Electronics Engineers, Calcutta, in 1977,
the S. K. Mitra Research Award in 1986 from the IETE for the best research
paper, the Indian National Science Academy Young Scientist Award in 1986,
the International Union of Radio Science Young Scientist Award in 1987,
the top Invention Award of the National Research Development Council
for his contributions to the indigenous development of ferrite phase shifter
technology in 1991, the VASVIK Award for the development of Ka-band
components and phase shifters in 1994, the Ram Lal Wadhwa Gold Medal
from the Institution of Electronics and Communication Engineers (IETE)
in 1995, the Academic Excellence Award from Indian Government for his
pioneering contributions to phase control modules for Rajendra Radar in
1998, the Shri Om Prakash Bhasin Award in the field of Electronics and
Information Technology in 2009, the Teaching excellence Award from IIT
Delhi in 2012, the Award for contributions made to the Growth of Smart
Material Technology by the ISSS, Bangalore in 2012, the Vasvik Award for the
contributions made to the area of Information, Communication Technology in
2012, the M. N. Saha Memorial Award from the IETE for the best application
oriented research paper in 2013, and the IEEE MTT Society Distinguished
Educator Award in 2014. He is the Chief Editor of the IETE Journal of
Research and an Associate Editor of the International Journal of Microwave
and Wireless Technologies, Cambridge University Press. He served as a
Distinguished Microwave Lecturer of the IEEE MTT-S from 2012 to 2014 and
as a Distinguished Microwave Lecturer-Emeritus of the IEEE MTT-S
in 2015.
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