Achieving Fully Autonomous System-on-Package Designs: An Embedded-on-Package 5G Energy Harvester within 3D Printed Multilayer Flexible Packaging Structures

Broadband Millimeter-Wave Textile-Based Flexible Rectenna for Wearable Energy Harvesting

“…For benchmarking purpose, a standard microstrip patch antenna has been simulated to validate the assumptions on the influence of the radiator's area on the antenna's efficiency, and to demonstrate the improvement of the proposed design over a standard design on the same substrate. Patch antennas have been widely reported in wearable mmWave antennas [23] and in low-cost additively manufactured rectennas [12], [14], [15]. The patch's dimensions are 9×7.125 mm with a 3.25 mm inset microstrip feed.…”

“…While the cut-off frequency is the frequency when the real and imaginary components of the diode impedance are equal, the diode's Power Conversion Efficiency (PCE) will be adversely reduced at frequencies approaching f cut−of f . Moreover, a significant portion of the energy at the output will always exist at the 1 st and 2 nd harmonics and not at DC [8], implying that proper harmonic termination is implemented at the output [7], [12], [14]. The cut-off frequency is defined in this work as the frequency where the resistance and the reactance of the diode are equal, and is given by…”

“…While it can be seen that the rectennas in [7] and [41] achieve higher efficiency due to the improved single-tone impedance matching, they both have lower load impedance (reducing the voltage sensitivity) in addition to being implemented on dedicated lowloss RF substrates allowing the implementation of large-area distributed elements matching networks. On the other hand, despite the high voltage sensitivity achieved by the 3D printed rectenna in [14], implemented on a lossy flexible 3D-printed substrate, the PCE is expected to be very low due to the high load impedance utilized to guarantee a 1 V DC output. Finally, to the best of the authors' knowledge, this is the first rectenna with a broadband 1 V sensitivity aimed at broadband mmWave 5G energy harvesting, in addition to being fabricated on textiles with a high-efficiency broadband antenna optimized for operation on-body.…”

“…Practical deployment of rectennas for radiative mmWave WPT and energy harvesting are dependent on the ability to deliver high power levels to the antenna. The rectenna proposed in this work, as well as in studies [7], [12], [14], require an input power in excess of 9.5 dBm to deliver a 1 V DC output across a resistive load (as compared in table II). Such a high power level may not be available as ambient radiation to be recycled from cellular communication.…”

“…In order to overcome the cost-barrier of mmWave rectennas fabricated on low-loss RF substrates, additive manufacturing has been used to realize mmWave rectennas for pervasive IoT [12], [14], [15]. While the reported additively manufactured rectennas achieve a 1-V output from as low as 10 dBm of mmWave power, they were all studied under single-tone excitation and are expected to have their bandwidth bottlenecked due to the use of patch antennas and narrow-band beamforming or array-feed networks.…”