Monopolar spline antenna for compact UWB tags

Depending on the application, an ultra-wideband antenna with omnidirectional radiation characteristics might sometimes be desired over a hemispherical one. To address this need, we have developed a compact, low-cost, and versatile monopolar spline antenna. This antenna is designed to operate across a wide frequency range from 4.6 GHz to 11 GHz, offering multi-channel coverage for Channels 3, 5, 6, 7, 8, and 9 according to the IEEE 802.15.4a-2011 standard. Despite its compact footprint, measuring only 18 mm by 17.5 mm with the ground plane and feed line included, the antenna maintains a high level of performance. It exhibits linear polarization with high polarization purity, making it a good choice for applications demanding purely polarized antennas or exploiting polarization diversity. Moreover, radiation efficiencies over 84% and stable radiation patterns with respect to frequency have been simulated. Fabrication is achieved in a cost-effective manner, by leveraging standard printed circuit board (PCB) technology and utilizing an inexpensive FR-4 substrate.

Prototype

Broadband operation in a compact antenna footprint IEEE 802.15.4a-2011 Channels 3 through 9 Footprint 18 mm x 17.5 mm Omnidirectional radiation pattern Standard PCB fabrication technology Facilitates integration of active electronics after ground plane extension Extremely low pulse distortion

Flexible printed UWB antenna for seamless integration onto curved surfaces

Specific ultra-wideband applications may necessitate antennas that are lightweight, affordable, and flexible, enabling seamless integration onto curved surfaces. Exploring unconventional materials and leveraging novel additive manufacturing techniques becomes particularly valuable in this context. Our team has extended its knowledge for the development of printed antennas, utilizing high-quality conductive ink applied to a thin, flexible substrate either by means of inkjet-printing or screen-printing. Several planar monopole antennas have been fabricated through the application of silver nanoparticle ink onto a 125 μm-thick polyethylene terephthalate (PET) foil. These prototypes are designed for various frequency bands, including Channel 5 and 9 in the IEEE 802.15.4a-2011 UWB standard . While possessing a compact footprint and structural flexibility, they provide stable operation and omnidirectional radiation patterns across a broad frequency range.

Broadband operation in a compact antenna footprint IEEE 802.15.4a-2011 Channels 5 through 9 Footprint 25 mm x 15 mm Omnidirectional radiation pattern Inkjet-printing fabrication technology Flexible substrate

Prototype

All textile cavity-backed slot antenna

For body-worn applications, an all-textile multi-moded cavity-backed slot antenna is designed and fabricated. This antenna covers Channels 2 and 3 of the IEEE 802.15.4a standard. Its light weight, mechanical flexibility, and small footprint of 35 mm x 56 mm facilitate integration into textile. The antenna features a stable radiation pattern and reflection coefficient in diverse operating conditions such as in free space, when subject to diverse bending radii and when deployed on the torso or upper right arm. The high isolation toward the wearer’s body originates from the antenna’s hemispherical radiation pattern with a -3 dB beamwidth of 120 degrees and a front-to-back ratio higher than 11 dB over the entire band. Moreover, the antenna exhibits a measured maximum gain higher than 6.3 dBi and a radiation efficiency over 75%.

Prototype

Broadband, efficient & suitable for body-worn UWB operation IEEE 802.15.4a-2011 Channels 2 and 3 Total efficiency > 75% Thickness: ~ 4 mm Mechanically flexible: all-textile implementation Compact integration of active electronics Robust performance in realistic deployment conditions Body-worn scenario Mechanical bending Extremely low pulse distortion within the half-power beamwidth

Low-profile active UWB antennas for challenging Industry 4.0 applications

Broadband, efficient operation in a low-profile package IEEE 802.15.4a-2011 Channels 1 through 7 Tailored radiation pattern Footprint <10 cm x 10 cm Thickness: < 7.5 mm Standard PCB fabrication technology Active electronics integrated on ground plane backside Stable performance when integrated on robot platform Extremely low pulse distortion within IEEE 802.15.4a-2011 Channels 2 and 5

Prototype