DUAL-POLARIZED, DIFFERENTIAL LINE FEED MICROSTRIP CIRCULAR PATCH ANTENNA FOR FULL DUPLEX COMMUNICATION

Transcription

1 DUAL-POLARIZED, DIFFERENTIAL LINE FEED MICROSTRIP CIRCULAR PATCH ANTENNA FOR FULL DUPLEX COMMUNICATION R.SOWMIYA2,B.SOWMYA2,S.SUSHMA2,R.VISHNUPRIYA2 2 Student T.R.P ENGINEERING COLLEGE Tiruchirappalli Sowmyabalakumar7@gmail.com Abstract In this paper, we present two dualpolarized microstrip circular patch antenna systems based on a single radiating element with 180 ring hybrid coupler for differential feeding to achieve high inter-port RF isolation. A frequency of 2.4GHz is used between the transmitter the receiver ports. Maximum amount of SI cancelation(sic) should be achieved at antenna stage to enable full duplex wireless communication operation at same frequency. In the proposed antenna circular patch is used for attaining high gain radiation. Microstrip patch antenna has poor isolation between 20-30dB ports. A dual-port dual-polarised microstrip patch antenna reported in achieves low cross-polarization inter-port isolation by using two different feeding methods for a single circular patch Furthermore the isolation can be further enhanced by employing a two hybrid input ports structure. Index terms: Differential antenna, fullduplex antenna, high RF isolation, selfinterference cancellation (SIC). 1. INTRODUCTION Full duplex is the modality of communication using the same carrier for simultaneous transmission reception of the same frequency b [1]. IBFD (In b full duplex) wireless is one of the emerging technology for next generation wireless networks currently being investigated for 5G networks as it as potential to double the data through put of wireless communication systems. Microstrip patch antenna are widely used as dual polarized elements due to their low profile, low cost, easy integration. Fig 1: Three ports microstrip patch antenna with slot coupled Tx port two Rx ports for differential Rx mechanism for SIC. In this communication, two dualpolarized, differential microstrip circular patch antennas are presented, based on three ports patch antenna differentially excited by ring hybrid Page 186

2 coupler for Rx mode operation to suppress the RF leakage from antenna s Tx port. Antenna have been fabricated using 1.6mm thick FR-4 substrate with tan =0.02 provide better than 50% radiation efficiencies [5]. 2. DUAL-POLARIZED DIFFERENTIAL FED MICROSTRIP CIRCULAR PATCH ANTENNA Dual-polarized antennas have been widely applied into present wireless communication system. High port to port RF isolation is achieved by using dual polarized microstrip As shown in Fig. 1, Tx polarization mode is excited by slot coupled port while the Rx polarization mode is excited through two co-planar λ/4 microstrip feeds with differential excitation. internal ground layer together with 180 phase shift excitation improves the cross-polarization purity consequently the isolation between ports. Antenna radiates in X, Y, Z axis. The simulated radiation characteristics endorse the dual polarized nature of proposed antenna for 2.4GHz frequency. The antenna is linear vertical polarized for one port linear horizontal polarized when the other port is excited with 4.15dBi gain for each port excitation. 3. ANTENNA ANALYSIS STRUCTURE AND Fig.3(a) Front view of microstrip circular Fig. 2. EM model for 180 ring hybrid coupler (designed using 1.6 mm thick FR4 substrate with r = 4.4 tan = 0.02). A 3 db ring hybrid coupler has been used as an external differential circuit to perform (S32 S12) operation when difference port of coupler is used as Rx port, port 1 port 3 of The complete design was fabricated on FR-4 epoxy substrate (with r = 4.4 tan = 0.02). Substrate layer is comprised of 1.6mm thick FR-4 substrate [5]. The port of hybrid coupler is terminated with 50Ω. The gain patterns for each port were measured by terminating ground port with 50Ω.This Fig.3(b) Back view of microstrip circular Fig 3(a) (b) are the proposed dualport dual-polarized microstrip patch Page 187

3 The dimensions of the inner outer circle of the circular patch are respectively. The thickness of the inner outer circle are 3mm [2].FR-4 epoxy substrate [with r =4.4, tangent loss=0.02, thickness(h=1.6mm) was used for antenna ring hybrid coupler implementation The Sparameter, VSWR, radiation pattern, gain, directivity of antenna will be calculated. 4. PERFORMANCE EVALUATION OF MICROSTRIP CIRCULAR PATCH ANTENNA Fig 4. Simulated S-parameter (return loss). The value of S-parameter is -21dB in this proposed Port 1 is designated as transmit port while port 2 port 3 are labelled as receiver ports, then in terms of S-parameters, we have S12=S13.Simualted measured two dimensional (2D) gain pattern for three port implemented microstrip patch antenna is designed [4]. The exploitation of in-b full-duplex (FD) in wireless communications targets to improve this efficiency by using the same resources to transmit receive, i.e., simultaneous transmission reception at the same carrier frequency. The radiating patch is excited for Tx operation through a small aperture/slot etched in ground plane which is swiched between two FR-4 layers as clear from Fig. 3(b). Fig 5. Simulated output of VSWR. 5. RESULTS AND DISCUSSION The optimum performance of the proposed antenna is achieved by the parametric studies carried out by HFSS its detailed optimum dimensions are given in Fig.3(a) 3(b). The comparison of existing proposed is given in table-1. Page 188

4 Fig 6: Simulated radiation pattern microstrip circular As clear from the simulation results shown, improved inter-port isolation between two orthogonal port is achieved between slot coupled Tx either of the Rx ports as compared to antenna co-planar feeds. patch TABLE-1 COMPARISON EXISTING AND ANTENNA Fig 7: Simulated gain of the microstrip circular The value of gain is increased to 4.154dB. BETWEEN PROPOSED S.NO PARAMETERS EXISTING PROPOSED 1. S-parameter -25Db -21dB 2. VSWR Gain 3.47dB 4.154dB 4. Directivity Radiation pattern Coverage area-180 >180 Fig 8: Simulated directivity of microstrip patch Thus, differential feeding through 180 ring hybrid coupler effectively achieves high interport isolation without effecting antenna s radiation performance [6]. The return loss measured at the two feeding ports of the prototype is presented in Fig.4 along with the simulated results [7]. Since the proposed antenna is able to achieve excellent gain radiation pattern level with good peak gains, it is therefore also possible for antenna array design CP radiation. 6. CONCLUSION A dual-feed dual-polarized microstrip antenna has been presented in this communication. Full duplex sets challenging design requirements on the wireless communication transceiver, especially in comparison with half duplex radios. Circular patch has been used in this proposed antenna to increase the gain, coverage as well as S-parameter. Page 189

5 REFERENCES [1] Haq Nawaz Ibrahim Tekin DualPolarized, Differential Fed Microstrip Patch Antennas With Very High Interport Isolation for Full-Duplex Communication. Dec 2017, pp [2] D. Korpi, L. Anttila, M. Valkama, Feasibility of in-b fullduplex radio transceivers with imperfect RF components: Analysis enhanced cancellation algorithms, in Proc. 9th Int. Conf. Cognit. Radio Oriented Wireless Netw. Commun. (CROWNCOM), Jun. 2014, pp [3] L. Anttila, D. Korpi, V. Syrjälä, M. Valkama, Cancellation of power amplifier induced nonlinear self-interference in fullduplex transceivers, in Proc. 47th Asilomar Conf. Signals, Syst. Comput., Nov. 2013, pp [4] H. Nawaz I. Tekin, Three dual polarized 2.4 GHz microstrip patch antennas for active antenna inb full duplex applications, in Proc. 16th Medit. Microw. Symp. (MMS), Abu Dhabi, United Arab Emirates, Nov. 2016, pp [5] B. Debaillie et al., Analog/RF solutions enabling compact full-duplex radios, IEEE J. Sel. Areas Commun., vol. 32, no. 9, pp , Sep [6] C. Y. D. Sim, C. C. Chang, J. S. Row, Dual-feed dual-polarized patch antenna with low cross polarization high isolation, IEEE Trans. Antennas Propag., vol. 57, no. 10, pp , Oct [6] H. Nawaz I. Tekin, Compact dual-polarized microstrip patch antenna with high interport isolation for 2.5 GHz in-b full-duplex wireless applications, IET Microw., Antennas Propag., vol. 11, no. 7, pp , Jun Page 190