The 8th European Conference on Antennas and Propagation (EuCAP 2014)
A Pattern-Reconfigurable Parasitic Patch Antenna Using BAR and HPND PIN Diode T. Sabapathy1, R. B. Ahmad2, M.Jusoh3, M.R.Kamarudin4, A.Alomainy5 1,2,3
School of Computer and Communication Engineering, Universiti Malaysia Perlis, Pauh Putra, Perlis, Malaysia
[email protected],
[email protected],
[email protected] 4 Wireless Communication Centre, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor,
[email protected] 5 School of Electronic Engineering and Computer Science, Queen Mary University of London,
[email protected]
Abstract—A pattern reconfigurable parasitic patch antenna using BAR and HPND PIN Diode is proposed. With parasitic element and mutual coupling technique, the presented antenna achieved beam switching at five phi of 0°, 45°, 135°, 225° and 315°. This is realized by four parasitic element surrounded a driven element. Each of the parasitic is shorted to the ground via a shorting pin. The ON and OFF state condition is control by the PIN Diode switch that embed to each parasitic element. This research studies the performance of different PIN Diode of BAR5002v and HPND-4005 in realizing the beam switching application. Index Terms—pattern switching, beam switching, parasitic patch antenna, BAR PIN Diode, HPND PIN Diode.
I.
INTRODUCTION
The reconfigurable antenna is the antenna that integrates with the RF switches to provide flexibility in terms of operating frequency, polarization and radiation pattern performance [1]. The developed multi-functional antenna will definitely reduce the antenna size; enhance system efficiency and decrease system cost and weight. There are two types of reconfigurable pattern;1) beam steering and 2) beam shaping. However, this research focusing more on the beam steering antenna. The pattern-reconfigurable can be achieved by using PIN Diode as a switching mechanism.The principal of the switch is to control the RF current flow to the desired path. However, the position of the switch is significantly considered. The switch impedance performance is typically related to the insertion and isolation of the PIN diode switch [2]. A switch in the ON - state or forward bias condition, ideally leads to the maximum of the transmission coefficient (S21), 100% of power is transmitted and reflection coefficient almost infinity which means 0% of power is reflected. To ensure minimum forward resistance (ON state) for BAR5002 and HPND4005 PIN Diodes, the 100mA current is required. In order to ensure the optimum isolation loss (ISO), BAR5002 PIN Diode required 0 volt of reverse voltage while HPND4005 needs at least 10 volt of reverse voltage. However, the beam steering antenna has a drawback to achieve high gain antenna at all desired directions (phi=0°,45°,135°,225°,315°) [3]. Moreover, the literature shows that it is difficult to achieve beam steering antenna with
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the stability in S11 [4]. Therefore, this research proposed a parasitic and mutual coupling to achieve both motivations. II.
ANTENNA DESIGN
Fig. 1 shows the structure of the proposed antenna design. The antenna is developed on the Taconic substrate with constant permittivity of 2.2 and thickness of 1.6 mm. It has a full ground plane with substrate size of 120 mm square. The proposed antenna with the capability of beam switching is design based on the parasitic and mutual coupling technique. Four parasitic elements denote as P1, P2, P3 and P4 have surrounded a center driven element as shown in Fig. 1 (a). Each of the parasitic and driven has radius of 23.7 and 23.6 mm respectively. The RF current is induced to the antenna via a coaxial probe feed as highlighted by the red circle. L1
L2
P2
P1
P3
P4
L3
L4
(a)
L5
(b) Fig.1. Antenna structure. (a) Front view. (b) Back view. For DC biasing, five inductors (L) with a value of 68 nH each are embed to the antenna which four L on the antenna’s front and one at the back of the antenna. Each of PIN Diode is integrated on each parasitic element. Moreover, four copper pins are shorted between the parasitic and ground plane.
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The 8th European Conference on Antennas and Propagation (EuCAP 2014)
Basically, the DC is excited from each inductor (L1, L2, L3 and L4). Then the DC will ON the PIN Diode and flows to the ground via a shorting pin. Each of the parasitic shared the similar inductor of L5 allows the current to have DC grounded. A performance comparison between BAR-5002 and HPND-4005 PIN Diode are investigated in achieving beam switching application since both switches have different impedance characteristics in ON and OFF condition. The BAR PIN Diode can support low frequency of 10MHz to 6 GHz only. The HPND PIN Diode operates from 1 GHz to 18 GHz. Besides, HPND has better S21 of 32 dB at 2.35 GHz if compared to BAR with 18 dB of ISO [5].Even, the HPND has a small foot-print dimension of 75% less than the BAR switch. III.
0 8 -30 7 6 5 60 -60 4 3 2 1 90 0 -90 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 HPND PIN Diode BAR PIN Diode 30
(c) P2 switch is OFF 0 8 -30 7 6 5 60 -60 4 3 2 1 90 0 -90 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 30
RESULTS AND DISCUSSION
The good mutual coupling between the driven and parasitic elements is significant in achieving better beam switching application. While the parasitic helps to pull and push the beam to the desired phi directions. Fig. 2 shows the simulated pattern of HPND and BAR PIN Diode. Both switches capable to achieve five beams switching at specific phi of 0°, 45°, 135°, 225° and 315°.When all switches are ON, the BAR has better gain of 9.3 dBi while HPND has gain of 8.8 dBi at particular theta of 0°.By turning OFF the P1 switch, the BAR steers theta to 20° with gain of 8.4 dBi and HPND steer theta to 23° with gain of 7.7 dBi as depicted in Fig. 2 (b). Fig. 2 (c) denotes a beam switching at theta of 20° and 23° for BAR and HPND respectively. While BAR has gain of 8.3 dBi compared to HPND gain of 7.9 dBi. When P3switch is OFF, the HPND has better theta angle of 26° while BAR steered thetaof20° as illustrated in Fig. 2(d).Fig. 2(e) shows whenP4 switch is OFF, the antenna with BAR integration has achieved beam steer at theta of20° and 24° angles for BAR and HPND respectively. Overall, the HPND achieved better beam theta as compared to BAR switch. However, the proposed antenna with BAR Diode has better gain with high side lobe than the HPND. 0 30
-30
8 6
60
-60
4
HPND PIN Diode BAR PIN Diode
(d) P3 switch is OFF 0 -30
30 8 7 6 5 -60 60 4 3 2 1 -90 0 90 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 HPND PIN Diode BAR PIN Diode
(e) P4 switch is OFF Fig.2.Simulated theta patterns via PIN diode configurations. CONCLUSION The great choice of HPND-4005 PIN Diode with low capacitance value (0.017pF) is really helping in achieving the better beam switching of theta=0°, 23°, 23°, 26° and 24°. In contrast the BAR PIN Diode has a higher capacitance value of 0.15 pF resulted to theta of 0°, 20°, 20°, 20° and 20°. Besides, the HPND has compact size than the BAR PIN Diode. ACKNOWLEDGEMENT The authors would like to thank to MOSTI (Vot 4S056).
2 90
0 8
6
4
2
-90 0
2
4
6
8
HPND PIN Diode BAR PIN Diode
[1]
(a) All switches are ON 0 30
-30 8 7 6 5 60 -60 4 3 2 1 90 0 -90 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 HPND PIN Diode BAR PIN Diode
[2]
[3]
[4] [5]
(b) P1 switch is OFF
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REFERENCES Huda A. Majid, M. K. A. R., M. Rijal Hamid &M.F. Ismail, “A Compact-Frequency Reconfigurable Narrowband Microstrip Slot Antenna”, IEEE Antennas and Wireless Propagation Letters, 11, 2012. Tamer Aboufoul, Alomainy, A. C., X., Parini, C.,“PatternReconfigurable Planar Circular Ultra-Wideband Monopole Antenna”,IEEE Transactions on Antennas and Propagation(99)1, 2013. Mohd Tarmizi Ali, M. N. M. T., T. A. Rahman, M. R. Kamarudin, M. F. Jamlos & R. Sauleau,“A Novel Reconfigurable Planar Antenna Array (RPAA) with Beam Steering Control”, Progress In Electromagnetic Research B, 20, 125-146, 2010. Z. Li, H. M., O. Kaynar and B.A. Cetiner,“Beam-steering antenna based on parasitic layer”,Electronic Letters, 48(2), 2012. Avagotech. (n.d.). PIN Diode HPND 4005 Datasheet.
