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A New Implementation of UWB CRLH Based Antennas for Wireless Communications

Alibakhshi-Kenari M., Naser-Mogaddasi M.

Journal of Telecommunications and Information Technology

2015

nr 1

42--52

In this article, a novel ultra wideband (UWB) small antennas based on the composite right/left-handed transmission lines structures are proposed. The antennas are pre- sented with best in size, bandwidth and radiation patterns. Their physical size and the operational frequency depend on the unit cell size and the equivalent transmission line model parameters of the CRLH-TL. To realize characteristics of frst proposed model, Q-shaped gaps printed into rectangular radiation patches are used. The antenna based on composite right/left-handed transmission lines is composed of two unit cells, each of which occupies only 10.8 x 8.6 mm and covers the 2.7{9.3 GHz bandwidth for VSWR < 2. The peak gain and radiation effciency, are 5.78 dBi and 42.1% 9.3 GHz, respectively. Moreover, the second designed antenna has the same size and enhancement bandwidth, gain and radiation effciency than the rst proposed antenna with similar design procedure. It is constructed of the printed Q-shaped four unit cells. The length, width and height are 21.6, 8.6 and 1.6 mm, respectively, and it covers 4.1{11.7 GHz bandwidth for VSWR < 2 having highest gain (7.18 dBi) and radiation effciency (92.69%) at 4.1 GHz.

Characterization of an aperture-stacked patch antenna for ultra-wideband wearable radio systems

Klemm M., Troester G.

Journal of Telecommunications and Information Technology

2005

nr 2

39-44

This paper presents, for the first time, the time-domain characteristics of an aperture-stacked patch antenna (ASPA) for ultra-wideband (UWB) wearable devices. The methodology of antennas characterization for UWB radio systems is also outlined. The antenna operates within the 3-6 GHz frequency band. Time- and frequency-domain characteristics of this antenna are presented in transmission mode (Tx), receiving mode (Rx) and for 2-antenna (Tx-Rx) system. The pulse driving the antenna has duration of 0.65 ns. In the Tx mode, pulses radiated in different directions of the H-plane have very similar shapes. Fidelity factors are as high as 91.6-99.9%. For 2-antenna system, pulses received in normal and end-fire-like directions have the fidelity of 69.5%. As it was found, antenna does not behave "reciprocal" comparing Tx and Rx modes. For normal propagation direction, radiated pulse is the 2nd derivative of the input waveform, but in the Rx mode, received pulse is the 1st derivative of the incident plane wave. This antenna can be used for transmission of short-pulses, even 0.65-1 ns in duration. It is also small (patch planar dimensions 32/19 mm) and compact. Microstrip configuration allows further integration of active devices on the same board. Taking into account above results we can say that ASPA is a good candidate for UWB non-invasive wireless body area network (WBAN) applications.