Design and simulation of an analog beamforming phased array antenna

International Journal of Electrical and Computer Engineering (IJECE)
Vol. 10, No. 2, April 2020, pp. 1398~1405
ISSN: 2088-8708, DOI: 10.11591/ijece.v10i2.pp1398-1405  1398
Journal homepage: http://ijece.iaescore.com/index.php/IJECE
Design and simulation of an analog beamforming
phased array antenna
Mohamed Elhefnawy
Department of Electrical Engineering, October 6 University, Egypt
Article Info ABSTRACT
Article history:
Received Mar 1, 2019
Revised Oct 10, 2019
Accepted Oct 17, 2019
In this paper, a phased array antenna is designed and simulated. The antenna
array consists of four circularly polarized slotted waveguide elements.
The antenna array is simulated using CST MWS. The simulation results for
the proposed antenna array at different values of progressive phase shift
demonstrate that the S‒parameters for all four ports are less than ‒10 dB over
at least 2% bandwidth, the simulated maximum gain is 13.95 dB,
the simulated beamwidth can be 19˚ or narrower based on the value of
the progressive phase shift. The range of frequencies over which
the simulated Axial Ratio (AR) is below 3 dB is not fixed and varied
according to the selected progressive phase shift. The proposed four-element
RF front-end is simulated using Advanced Design System (ADS) at
operating frequency of 9.6 GHz. The obtained simulation results by ADS
indicate the feasibility of implementing the proposed RF-front end for
feeding the antenna array to realize analog beamforming.
Keywords:
Analog beamforming
Circular polarization
Phased array antenna
RF front-end
Slotted waveguide antenna
Copyright © 2020 Institute of Advanced Engineering and Science.
All rights reserved.
Corresponding Author:
Mohamed Elhefnawy,
Department of Electrical Engineering,
October 6 University,
6th of October City, Egypt.
Email: mmmelhefnawy.eng@o6u.edy.eg
1. INTRODUCTION
Phased array antenna with analog beamforming is regarded in order to improve the performance of
wireless communication systems by increasing the coverage area and decreasing the interference. In analog
beamforming technology, the phase of each signal received and transmitted by the antenna array element is
adjusted, so that the radiation pattern of the antenna array is steered in the desired direction. The IF phase
shifting is implemented in this research because it can provide much better performance compared to RF and
LO phase shifting [1-14]. The slotted waveguide antenna array is selected because it can provide high power
handling capability, low loss, small size, narrow beamwidth, good bandwidth, and high gain [15-25]. This
paper is organized as follows. The design of the proposed antenna array element is explained in Section 2.
The architecture of the proposed phased array system is introduced in Section 3. In Section 4, the simulation
results are presented. The conclusions are provided in Section 5.
2. DESIGN OF THE PROPOSED ANTENNA ARRAY ELEMENT
For the proposed Slotted Waveguide Antenna Array (SWAA), the broad wall width of
the rectangular waveguide is selected to make the cut-off frequency of TE10 mode is 86.9% of the operating
frequency at 9.6 GHz. The narrow wall width of the rectangular waveguide is selected to be half the broad
wall width. The waveguide wavelength (𝜆 𝑔) is calculated as [19]

Int J Elec & Comp Eng ISSN: 2088-8708 
Design and simulation of an analog beamforming phased array antenna (M. Elhefnawy)
1399
𝜆 𝑔 =
1
√
1
𝜆2−
1
𝜆 𝑐
2
(1)
where 𝜆 𝑐 is the cutoff wavelength at the operating mode. There is a phase shift of (π/2) between the generated
waves from the longitudinal slot fields (slot #1 and slot #3) and the wave produced by the transversal slot
fields (slot #2 and slot #4). The Right Hand Circular Polarization (RHCP) is obtained by optimizing the slot
offset from the central longitudinal line in order to change the value of 𝐸 𝐿 to be equal to the value of 𝐸 𝑇,
where 𝐸 𝐿, 𝐸 𝑇 are magnitudes of the resultant waves from the longitudinal and transversal slot fields,
respectively, as shown in Figure 1.
Figure 1. Structure of the resonating circularly polarized SWAA
3. THE ARCHITECTURE OF THE PROPOSED PHASED ARRAY SYSTEM
The proposed phased array antenna consists of four-element slotted waveguide antenna array and
the RF front-end to feed the antenna array. The block diagram of the proposed phased array antenna is shown
in Figure 2. In the receiving mode, the RF front-end has four channel; and two-stage down-conversion
(9.6 GHz to 2.4 GHz & 2.4 GHz to 400 MHz). Also in the transmitting mode, there are other four channel;
and two-stage up-conversion (400 MHz to 2.4 GHz & 2.4 GHz to 9.6 GHz). Each channel in the receiving
mode amplifies, down-converts (9.6 GHz to 2.4 GHz), adjusts the phase of, and demodulates the incoming
signal from the antenna array element. The Wilkinson power combiner is used to combine the four signals
coming from the antenna array to one signal which is entered to the I/Q demodulator to be down-converted
again from 2.4 GHz to 400 MHz. The demodulated (I&Q) complex signals are fed to the input of the analog
to digital converter (ADC). In the transmitting mode, the (I&Q) signals from the digital to analog conversion
(DAC) are modulated and up-converted from 400 MHz to 2.4 GHz, then it is divided into four identical
signals, each signal is transmitted through different channel, and its phase is adjusted then up-converted from
2.4 GHz to 9.6 GHz, then it is filtered and amplified before transmitting to the antenna array element.
The power detector is used to monitor the received signal power, and then the control part is implemented to
change the progressive phase shift if the received power is lower than a threshold value. The antenna array is
aligned in a 4×1 linear array with center to center distance between the adjacent elements of 0.705𝜆 as shown
in Figures 3(a), and 3(b), the dimensions of the proposed slotted waveguide antenna element is indicated in
Table 1.
Table 1. Dimensions of the Proposed Antenna Array Element
Parameter Dimensions (mm)
Wavelength in the waveguide 𝜆g 63.1875
Broad-wall width of the rectangular waveguide 18
Narrow-wall width of the rectangular waveguide 9
Wavelength 𝜆 31.25
Slot length 15.390625
Slot width 1.204
Slot offset from the central longitudinal line 7.447
Monopole length 7.8125

 ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 10, No. 2, April 2020 : 1398 - 1405
1400
Figure 2. Block diagram of the proposed phased array antenna
(a)
(b)
Figure 3. Geometry of the proposed SWAA: (a) Perspective view, (b) Cross-sectional plane view
4. SIMULATION RESULTS
The proposed antenna array is simulated using CST MWS, at an operating frequency of 9.6 GHz.
The S-parameters for all four ports are below ‒10 dB over frequency range from 9.5 GHz to 9.7 GHz as
shown in Figure 4. The simulated two-dimensional and three-dimensional radiation patterns are shown in
Figures 5 and 6, respectively. The beam width is below 19°
, and the antenna gain is at least 13.38 dB.
(a) (b)
Figure 4. Simulated S-parameters for the proposed SWAA: (a) Progressive phase shift=0°
,
(b) Progressive phase shift=±45°
Circulator
Mixer with
image rejection
MixerBPF
LN
PA
T/R
switch
Circulator
Mixer with
image rejection
MixerBPF
LN
PA
T/R
switch
Phase
shifter
Wilkinson
Power
divider/
combiner
Circulator
I/Q
demod
ulator
I QController
Power
detector
Phase
shifter
I/Q
modulator
I
Q

1401
(a) (b)
(c)
Figure 5. Simulate two-dimensional radiation pattern for the proposed SWAA: (a) Progressive phase
shift=0°
, (b) Progressive phase shift=45°
, (c) Progressive phase shift=−45°
(a) (b)
(c)
Figure 6. Simulated three-dimensional radiation pattern for the proposed SWAA; (a) Progressive phase
shift=0°
, (b) Progressive phase shift = 45°
, (c) Progressive phase shift=−45°

 ISSN: 2088-8708
1402
The proposed antenna array is circularly polarized over frequency range from 9.5 GHz to 9.7 GHz,
but the purity of the circular polarization decreases as the progressive phase is far from 0°
as shown
in Figure 7. The RF transceiver front-end is simulated using ADS as shown in Figure 8. In receiving mode,
the incoming signal from each antenna array element is entered to any port of the circulator (TRAK
Microwave Corporation X-Band SMT Circulator) to be transmitted to the next port in rotation, while
the other port is isolated, then the signal is amplified by Mini-circuits PMA2-123LN+ low noise amplifier
(LNA), and then it is down-converted from 9.6 GHz to 2.4 GHz by ANALOG DEVICES HMC1056LP4BE
mixer. LNA is simulated by calling the S2P file of PMA2-123LN+ in the ADS. HMC1056LP4BE mixer
consists of two balanced mixers and quadrature hybrid at the input, another quadrature hybrid is connected at
its output to make this mixer works as an image rejection mixer which has the ability to select the desired
signal and cancel out the image signal. One of these quadrature hybrids is designed at 9.6 GHz and is used to
split the RF input into inphase and quadrature signals, the other quadrature hybrid is designed at 2.4 GHz and
used to add 90 degrees phase shift between the two IF outputs before combining them together. The SPDT
RF switch (Mini-circuits CSWA2-63DR+) is implemented to switch between the transmitting and receiving
mode. The first stage IF signal (2.4 GHz) is applied to the digital phase shifter (MACOM MAPS-010144),
there is one digital phase shifter for each channel to adjust the progressive phase of the received signal in
order to maximize the received signal power. This digital phase shifter is simulated in ADS by calling
the S2P file. The 4×1 Wilkinson power divider/combiner is designed using ADS. The I/Q demodulator
(ANALOG DEVICES ADRF6821) is simulated in ADS. A quadrature hybrid is designed at 2 GHz to split
the output from the local oscillator into two quadrature signals.
The outputs from I/Q demodulator are entered to the variable gain amplifier VGA (ANALOG
DEVICES ADRF6520) to adjust this I/Q signals in order to fit within the input range of the next stage.
If the I/Q signals are small, then the VGA will gain up these signals; while if it exceed that range, VGA will
attenuate these I/Q signals. Also this VGA (ANALOG DEVICES ADRF6520) has a built in programmable
filter to filter up the I/Q signals before ADC in order to prevent the aliasing content from being sampled.
The frequency domain analysis is done by using Harmonic Balance (HB) simulation technique in ADS to
determine the spectral contents for the RF receiver front-end. For I and Q channels at the output of I/Q
demodulator, Figure 9 shows that the spectral with frequency 400 MHz has maximum value and other
spectral contents can be ignored. The I/Q output signals from the DAC is upconverted from 400 MHz
to 2.4 GHz by using I/Q modulator (ANALOG DESVICES ADRF6821). The output from the I/Q modulator
is divided into four signals by using 4×1 Wilkinson power divider, then the phase of each signal is adjusted,
after that the signal is upconverted from 2.4 GHz to 9.6 GHz by using the mixer (ANALOG DEVICES
HMC553ALC3B). VGA (ANALOG DEVICES HMC996LP4E) is used to fit the mixer’s output to the input
range of the next stage. The signal is passed through the band pass filter with center frequency 9.6 GHz
(K&L Microwave, Inc 3FV20-9600/T300-SM/SM), then amplified by the power amplifier (ANALOG
DEVICES HMC7149) before transmitted through the circulator to the antenna array element.
The transmitter’s variable gain amplifier, band pass filter, and power amplifier are simulated in ADS by
calling their S2P files. Figure 10 shows the frequency domain analysis for the RF transmitter front-end at
the inputs of the antenna array elements, where all spectral contents can be ignored compared to the spectral
with frequency of 9.6 GHz.
Figure 7. Simulated Axial Ratio (AR) versus frequency for the proposed SWAA at different values of
the progressive phase shift

1403
Figure 8. ADS simulation model for the proposed RF transceiver front-end
Figure 9. Frequency domain analysis at the output of I/Q demodulator for the RF receiver front-end

 ISSN: 2088-8708
1404
Figure 10. Frequency domain analysis at the inputs of the antenna array elements for
the RF transmitter front-end
5. CONCLUSION
In this paper, the analog beamforming is realized by designing a proposed phased array antenna
which operates at 9.6 GHz, and consists of 4×1 slotted waveguide antenna array with RF transceiver front-
end as a feeder. The slotted waveguide antenna array is simulated in CST MWS; the simulation results show
that the proposed phased array antenna can achieve a maximum gain of 13.95 dB, a beam width equal or less
than 19°
in the elevation plane, and S-parameters below‒10 dB over the frequency range from 9.5 GHz
to 9.7 GHz. The purity of the circular polarization depends on the value of the progressive phase shift.
The ADS simulation software is used to simulate the proposed RF transceiver front-end. The ADS simulation
results show the possibility of using the proposed RF transceiver front-end as a feeder for the slotted
waveguide antenna array to obtain analog beamforming at 9.6 GHz.
REFERENCES
[1] D. Ehyaie, “Novel Approaches to the Design of Phased Array Antennas,” Doctor of Philosophy. The University of
Michigan, 2011.
[2] G. L. Charvat, L. C. Kempel, E. J. Rothwell, C. M. Coleman, and E. L. Mokole, "An Ultrawideband (UWB)
Switched-Antenna-Array Radar Imaging System," IEEE International Symposium on Phased Array Systems and
Technology, Waltham, MA, pp. 543-550, 2010.
[3] M. T. Islam, N. Misran, and B. Yatim, “Smart Antenna UKM Testbed for Digital Beamforming System,”
EURASIP Journal on Advances in Signal Processing, 2009. DOI: 10.1155/2009/128516.
[4] W. Wang, J. Wang, D. Liang, Y. Tian, and T. Ren, "Development of RF Front-End for Real-Time MIMO Radar
Imaging System," Sixth International Conference on Instrumentation & Measurement, Computer, Communication
and Control (IMCCC), Harbin, pp. 968-973, 2016.
[5] M. Hossu, S. H. Jamali, P. Mousavi, K. Narimani, M. Fakharzadeh, and S. Safavi-Naeini, "Microwave
Beamforming using Analog Signal Processing," IEEE Antennas and Propagation Society International Symposium,
San Diego, CA, pp. 1-4, 2008.
[6] N. A. Malek, O. O. Khalifa, Z. Z. Abidin, S. Y. Mohamad, and N. A. A. Rahman, "Beam Steering using the Active
Element Pattern of Antenna Array," TELKOMNIKA, vol.16, no.4, pp. 1542-1550, August 2018.
[7] H. Xu, H. Aliakbarian, and G. A. E. Vandenbosch, "Off-the-Shelf Low-Cost Target Tracking Architecture for
Wireless Communications," IEEE Systems Journal, vol. 9, no. 1, pp. 13-21, March 2015.
[8] R. Rotman, M. Tur, and L. Yaron, "True Time Delay in Phased Arrays," Proceedings of the IEEE, vol. 104, no. 3,
pp. 504-518, March 2016.
[9] D. L. Lemes, M. V. T. Heckler, and A. Winterstein, "A Low-Cost Modular Transmit Front-End with Analog
Beamforming Capability," SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC),
Aguas de Lindoia, pp. 1-5, 2017.
[10] Y. Yao, F. Zhang and F. Zhang, "A New Approach to Design Circularly Polarized Beam-Steering Antenna Arrays
Without Phase Shift Circuits," in IEEE Transactions on Antennas and Propagation, vol. 66, no. 5, pp. 2354-2364,
May 2018.
[11] Y. Yashchyshyn, K. Godziszewski, G. Bogdan and P. Piasecki, "X-band antenna array for low-cost beam
scanning," in IET Microwaves, Antennas & Propagation, vol. 11, no. 15, pp. 2174-2178, 10 12 2017.
[12] H. Zhu, H. Sun, B. Jones, C. Ding and Y. J. Guo, "Wideband Dual-Polarized Multiple Beam-Forming Antenna
Arrays," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 3, pp. 1590-1604, March 2019.

1405
[13] R. Baggen, S. Holzwarth, M. Bottcher and S. Otto, "Innovative Antenna Front Ends from L-Band to Ka-Band
[Antenna Applications Corner]," in IEEE Antennas and Propagation Magazine, vol. 59, no. 5, pp. 116-129, Oct.
2017.
[14] A. S. Y. Poon and M. Taghivand, "Supporting and Enabling Circuits for Antenna Arrays in Wireless
Communications," in Proceedings of the IEEE, vol. 100, no. 7, pp. 2207-2218, July 2012.
[15] M. W. Sabri, N. A. Murad, and M. K.A. Rahim, "Bi-directional Beams Waveguide Slotted Antenna at Millimeter
Wave," TELKOMNIKA, vol. 16, no. 4, pp. 1515-1521, August 2018.
[16] A. Oliner, "The Impedance Properties of Narrow Radiating Slots in the Broad Face of Rectangular Waveguide:
Part I--Theory," IRE Transactions on Antennas and Propagation, vol. 5, no. 1, pp. 4-11, January 1957.
[17] M. Orefice and R. S. Elliott, "Design of Waveguide-Fed Series Slot Arrays," Microwaves, Optics and Antennas,
IEEE Proceedings H, vol. 129, no. 4, pp. 165-169, August 1982.
[18] R. K. Enjiu and Perotoni M. B., "Slotted Waveguide Antenna Design using 3D EM Simulation," Microwave
Journal, Horizon House Publications, 2013.
[19] S. Rozenberg and A. Yahalom, "A THz Slot Antenna Optimization using Analytical Techniques,"
RADIOENGINEERING, vol. 25, no. 1. Sep. 2016.
[20] B. Pyne, P. R. Akbar, V. Ravindra, H. Saito, J. Hirokawa and T. Fukami, "Slot-Array Antenna Feeder Network for
Space-Borne X-Band Synthetic Aperture Radar," in IEEE Transactions on Antennas and Propagation, vol. 66, no.
7, pp. 3463-3474, July 2018.
[21] P. Kumar, A. Kedar and A. K. Singh, "Design and Development of Low-Cost Low Sidelobe Level Slotted
Waveguide Antenna Array in X-Band," in IEEE Transactions on Antennas and Propagation, vol. 63, no. 11,
pp. 4723-4731, Nov. 2015.
[22] H. Guan-Long, Z. Shi-Gang, C. Tan-Huat and Y. Tat-Soon, "Broadband and high gain waveguide-fed slot antenna
array in the Ku-band," in IET Microwaves, Antennas & Propagation, vol. 8, no. 13, pp. 1041-1046, 21 October
2014.
[23] A. Ghasemi and J. Laurin, "A Continuous Beam Steering Slotted Waveguide Antenna Using Rotating Dielectric
Slabs," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 10, pp. 6362-6370, Oct. 2019.
[24] Y. Tyagi, P. Mevada, S. Chakrabarty and R. Jyoti, "High-efficiency broadband slotted waveguide array antenna," in
IET Microwaves, Antennas & Propagation, vol. 11, no. 10, pp. 1401-1408, 16 8 2017.
[25] H. C. Zhao, R. R. Xu and W. Wu, "Broadband waveguide slot array for SAR," in Electronics Letters, vol. 47, no. 2,
pp. 76-77, January 2011.
BIOGRAPHY OF AUTHOR
Mohamed Elhefnawy received PhD degree in Communications Engineering from USM
University, Malaysia, in 2010. He has strong academic background that includes: RF/Microwave
Engineering, Electromagnetic Theory and Antenna Theory. He has a particular set of skills in
Electromagnetic simulation tools such as ADS and CST, and Simulation of Systems using
MATLAB and Simulink. In addition to his expertise in antenna design, he has experience in
designing and testing RF/Microwave components such as amplifiers, mixers, oscillators, and
microwave filters. He got “Sanggar Sajung” Award for Excellence in Publishing, University of
Science Malaysia (USM), 2009. He published high impact factor research papers.

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