2018 International Symposium on Antennas and Propagation (ISAP 2018) [WeA2-4] October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

A Planar 3.4−9 GHz UWB Monopole

Md Nazmul Hasan, and Munkyo Seo School of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea Email: [email protected], [email protected]

Abstract – A planar omnidirectional UWB is presented. It consists of a rectangular radiator containing two triangular and one circular sector slots which contribute to wideband impedance matching. The measured impedance bandwidth is 3.4−9 GHz where |S11|  −10 dB. The proposed antenna has omnidirectional radiation patterns with linear polarization. Measured group delay variation of the antenna is 0.5 ns over the operating bandwidth. Having a compact size of 40×40×1.52 mm3, the proposed antenna is suitable for integration in handheld UWB devices. To validate the design, a prototype antenna is fabricated and tested. Fig. 1. Proposed antenna (a) top, (b) bottom, (c) fabricated

Index Terms — Planar antenna, monopole antenna, UWB antenna, omnidirectional antenna, group delay.

1. Introduction

Ultra wideband (UWB) technology has paved the way for high speed short-range communication. In terms of performance and ease of integration in portable devices, planar compact printed antennas have proved to be unrivaled. A UWB antenna has a fractional bandwidth greater than 20% Fig. 2. |S11| of the antenna (with and without slots) or occupies an impedance bandwidth of 500 MHz or more [1]. A compact metamaterial based UWB antenna is reported in [2]. Bandwidth enhancement technique for planar TABLE I monopole UWB antenna is reported in [3], while quad-band Dimensional Parameters of the Proposed Antenna notch property within UWB spectrum is designed in [4]. Parameter Value Parameter Value Parameter Value Recently, an on-body UWB antenna is proposed in [5]. (mm) (mm) (mm) Several other UWB antennas are reported in [6−10]. W 40 s 3.66 i 6.6 This work presents a compact, printed UWB monopole L 40 r 3 j 9.2 antenna with 90.3% fractional bandwidth (3.4−9 GHz). The m 20 u 4.5 l 12.5 proposed antenna shows omnidirectional patterns with a n 16 v 1.5 G 11.95 measured group delay variation less than 0.5 ns, ensuring dispersion-free transmission and reception characteristics. Section 2 presents antenna configuration, while section 3 3. Measured Results presents the measured results followed by conclusion. The proposed antenna is designed in HFSS and measured in anechoic chamber with Agilent E8364B network analyzer. 2. Antenna Configuration Fig. 3 depicts the measured impedance bandwidth which is The proposed antenna, as shown in Fig.1(a), consists of a 3.4−9 GHz. The measured radiation patterns at different rectangular radiator loaded with two triangular slots, and a frequencies are omnidirectional as shown in Fig. 4. The circular sector slot on a Taconic RF-30 substrate having a group delay is measured by placing the two identical antenna thickness of 1.52 mm. The relative permittivity and tangent prototypes face-to-face, 15 cm away in their far-field region. loss of the substrate are 3.0 and 0.0014 respectively. A As shown in Fig. 5, the measured group delay variation is partial plane is used and the length G is optimized for less than 0.5 ns. To ensure dispersion-free communication, wideband impedance matching as shown in Fig. 1(b). Fig. group delay variation of a UWB antenna should be less than 1(c) shows the fabricated antenna. The antenna is fed by 50 1 ns [11]. Table II compares the proposed antenna with other Ω microstrip line. The slots on the radiator improves works. The proposed antenna offers a reasonable trade-off impedance matching of the proposed antenna as shown in between size and impedance bandwidth. Fig. 2. Dimensional parameters of the proposed antenna are listed in Table I.

79 2018 International Symposium on Antennas and Propagation (ISAP 2018) October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

TABLE II Comparison of the Proposed Antenna with Other Works 3 Reference Bandwidth (GHz) Size (mm ) (for |S11|−10 dB) This work 3.4−9.0 40×40×1.52 [3] 3.75−6.8; 8.5−11.2 30×10×1.6 [4] 3.0−12 21×14×0.8 [5] 3.0−7.0 50×50×11.52a

[6] 1.6−13.2 50.9×50.9×1.6b

[7] 1.2−4.43 60×30×1.6 Fig. 3. |S11| of the proposed antenna [8] 0.05−5.0 60×72.8×1.6

auses a backside reflector; bsimulation based work E-plane H-plane

4. Conclusion

A compact omnidirectional UWB antenna is designed,

fabricated and tested, yielding an impedance bandwidth from

3.4−9 GHz with a group delay variation less than 0.5 ns. The

proposed antenna occupies a small footprint of 40×40×1.52

mm3, making it suitable for portable devices. Post-

fabrication revision of the antenna revealed that the antenna

size can be reduced to 30×30×1.52 mm3 while maintaining (a) similar or better impedance bandwidth.

Acknowledgment

This work was supported by a grant from the Ministry of

Trade, Industry & Energy (MOTIE, South Korea) under

Industrial Technology Innovation Program No. 10067194,

‘Human detection sensor under obstructed conditions’.

(b) References [1] D. Ghosh et al., “Transmission and Reception by Ultra-Wideband (UWB) Antennas”, IEEE Antennas Prop. Mag., vol. 48, no. 5, pp. 67−99, Oct. 2006. [2] G.K. Pandey, H.S. Singh, P.K. Bharti, and M.K. Meshram, “Metamaterial-based UWB Antenna”, Electron. Lett., vol. 50, no. 18, pp. 1266−1268, Aug. 2014. [3] R. Adacci et al., “Simple Bandwidth Enhancement Technique for Miniaturised Low-profile UWB Antenna Design”, Electron. Lett., vol. 50, no. 22, pp. 1564−1566, Oct. 2014. [4] H. Hosseini, H.R. Hassani, and M.H. Amini, “Miniaturised multiple notched omnidirectional UWB monopole antenna”, Electron. Lett., vol. 54, no. 8, pp. 472−474, Apr. 2018. [5] E. Miralles, C. Andreu, M.C. Fabrés, M.F. Bataller, and J.F. Monserrat, “UWB On-body Slotted Patch Antennas for In-body (c) Communications”, in Proc. European Conference on Antennas and Propagation (EuCAP), 2017, Paris, France, pp. 167−171. Fig. 4. Radiation patterns at (a) 4 GHz, (b) 6 GHz, (c) 8 GHz [6] S.R. Patre, and S.P. Singh, “Leaf-shaped Log-periodic for Broadband Applications”, in Proc. International Symposium on Antennas and Propagation (ISAP), 2017, Phuket, Thailand. [7] C.L. Tsai, and C.L. Yang “Novel Compact Eye-Shaped UWB Antennas”, IEEE Antenna Wireless Propag. Lett., vol. 11, pp. 184−187, 2012. [8] A. Munir, R.B.V.B. Simorangkir, “Performance Enhancement of Cavity-backed UWB Printed Monopole Antenna”, in Proc. Asia- Pacific Conference (APMC), 2017, Kuala Lumpur, Malaysia, pp. 584−587. [9] M.N. Hasan, and M. Seo, “High Gain 2×2 UWB with Integrated Phase Inverter”, Electron. Lett., vol. 54, no. 10, pp. 612−614, May 2018. [10] K. Bahadori, and Y.R. Samii, “A Miniaturized Elliptic-Card UWB Fig. 5. Group delay (face-to-face configuration, d = 15 cm) Antenna with WLAN Band Rejection for Wireless Communications”, IEEE Trans. Antennas Propag., vol. 55, no. 11, pp. 3326−3332, Nov. 2007.

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