Meshed High-Impedance Matching Network-Free Rectenna Optimized for Additive Manufacturing

Abstract

Additive manufacturing using direct-write or screen printing represent low-waste methods for fabricating antennas on low-cost flexible substrates. To realize rectennas using low-resolution printing methods, high-impedance antennas with simple printable geometries are required. This article proposes an electrically-small (0.212×0.212λ 2 ) folded dipole antenna design with a scalable impedance for directly matching energy harvesting rectifiers. The antenna is demonstrated in a high-efficiency sub-1 GHz rectenna, with varying mesh fill-factors for optical transparency. The proposed solid (non-transparent) and meshed (70%-transparent) rectennas achieve a Power Conversion Efficiency (PCE) of over 70% and 60% from sub-1 μW/cm 2 power densities, at 940 and 920 MHz, respectively. This represents a 37% improvement in the PCE over state-of-the-art flexible rectennas while maintaining the smallest electrical size and simplest design by not requiring a matching network. The 70%-transparent rectenna's performance is investigated in real-life use-cases showing its suitability for ambient RF energy harvesting with over 500 mV DC output from a phone-call.INDEX TERMS Antennas, dipole antennas, microstrip antennas, printed antennas, rectennas, rectifiers, RF energy harvesting, transparent antennas, wireless power transfer.

Dual-Band Dual-Mode Textile Antenna/Rectenna for Simultaneous Wireless Information and Power Transfer (SWIPT)

“…Fig. 15 shows the test setup of the proposed antenna, the same setup from [10] and [51]. The communications port was terminated using a 50Ω SMA termination.…”

Dispenser Printed Flexible Rectenna for Dual-ISM Band High-Efficiency Supercapacitor Charging

“…1-c. The antenna was fabricated using direct-write dispenser printing using a Voltera V-One printer and flexible silver ink, using the process detailed in [13] and [10]. The antenna was printed on a flexible 75 µm polyimide (Kapton) substrate with r =3.4 and tanδ=0.02.…”

“…P RF is assumed to be 1 dBm based on the calculated incident power density S=7.4 µW/cm 2 and a receiving antenna gain of 2.1 dBi. By using the gain of a typical λ/2 dipole, the antenna effect as well as the rectification losses are factored in the PCE, enabling holistic evaluation of the rectenna [10]. In Fig 6-b (solid line), it can be observed that in approximately 5 seconds in very close proximity (3-5 cm) from a 446 MHz handheld radio, the rectenna harvests 47.6 mJ.…”

“…Realizing rectennas using additive manufacturing has attracted significant interest due to the potential for reducing the rectenna's cost [8], and for enabling rectennas on a variety of substrates. 2.4 GHz [9], sub-1 GHz [10], [11], and millimeterwave [2], [12] rectennas have been realized using directwrite inkjet and dispenser printing. In [11], where the printed rectenna was used to power a sensor node, the DC power management circuity, owing to its high-complexity, was integrated on a rigid PCB housing multiple lumped components.…”

Towards the Optimal RF Sensing Strategy for IoT Applications: An Ice Sensing Case Study

“…The designed antennas have been fabricated on a flexible polyimide substrate of 75 µm thickness. Direct-write dispenser printing, recently demonstrated for energy harvesting [33] and IoT antenna prototyping [34], has been utilized to deposit the silver tracks on the organic polymer substrate. The printer used is a commercially-available Voltera V-one printer, intended for rapid and low-cost PCB prototyping.…”