Abstract Using wireless transmitters to create an ocean of radio frequency RF energy and to power remote devices have been a dream since Nikola Tesla invented wireless communications. Recently, wireless power technology has been embedded into a plethora of consumer electronics to improve device reliability and extend battery life. Soon enough, miniature wireless sensors adapting microwave energy harvesting modules for power will be located at spots where it would be otherwise inconvenient, such as, to change their batteries.
Comparison of simulated and measured copolarization radiation patterns in -plane a and -plane b in the band GSM Comparison of simulated and measured copolarization radiation patterns in -plane a and -plane b in the 3G band.
Comparison of simulated and measured copolarization radiation patterns in -plane a and -plane b in the WiFi band. Double Koch Slot Loop Antenna In this part, we design a double Koch slot loop antenna, which is equivalent to the electrical monopole according to the duality theorem.
The Koch fractal provides the opportunity to prolong the magnetic current line of the antenna. Therefore, we are able to design the antenna with smaller dimensions, while maintaining the same resonant frequency. The antenna structure is optimized to operate at two resonant frequencies GHz and GHz.
Impedance matching and radiation pattern at two resonant frequencies are the main objectives of the design. The procedure allows prolonging the physical length of the designed structure by factorwhere is the number of the iteration, but the final dimension of the structure is still the same.
The designed double slot loop antenna consists of two Koch snowflake shapes created from the third and second iteration of the Koch fractal, respectively see Figure Geometrical configuration of the dual Koch slot antenna. The length of this slot loop is given bywhere indicates the length of a straight slot.
The loop is interrupted by a narrow strip of 2 mm width, which plays role of a serial susceptance in the circuit of a magnetic current used for tuning the input impedance of the antenna.
The smaller loop resonates at higher frequency GHz and uses the second iteration of Koch fractal. Length of this slot loop is given bywhere indicates the length of a straight slot, but it is necessary to add small part of larger slot from feeding line to point of both slots connection.
Both sides of this slot are incurved in the angle of The antenna was designed on the FR4 substrate with relative permittivitydielectric loss tangent approximatelyand height mm. The prototype of the antenna was completed by a SMA connector.
The measured reflection coefficient of the designed antenna is depicted in Figure 3. The antenna covers the required bands with very good value of the reflection coefficient and a certain margin.
The radiation patterns were measured in one of the principal planes only due to the limitations of our measurement setup i. It was impossible to mount the antenna in the test range in order to measure its -plane.
Due to this reason, simulated values are compared with measured ones for the -plane in Figure Comparison of simulated and measured copolarization radiation patterns in -plane in the bands GSM a and WiFi b.
Modified Dual-Band Inverted F Antenna IFA In recent years, the IFA antenna received particular attention as a promising candidate for decimeter-wave applications due to its simple structure, integration, small size, low profile, and low cost. From the viewpoint of size, the IFA arm covers larger space than a quarter of wavelength.
The IFA seems a good candidate for energy harvesting due to its compact size, sufficient bandwidth, high efficiency, and relatively straightforward design. However, due to additional capacitor which was required, the antenna design ceased to be that simple. The usage of two independent resonant elements at the desired GSM frequencies can be considered innovational.
The top and bottom view of the proposed antenna are depicted in Figure The antenna is created by 2 rectangular planar stubs placed at the opposite side of the ground plane achieving two fundamental resonant frequencies in both GSM bands: Each individual stub is shorted by a metallic via.
The short circuits are located on the left side.
A coaxial SMA connector is used for feeding. Geometrical configuration of the proposed antenna: The width of the stubs is established for sufficient impedance matching to the coaxial connector.
The final dimensions of the proposed IFA antenna are stated in Table 1. Parameters of the proposed IFA antenna. To verify the designed IFA antenna experimentally, the antenna was fabricated on a thin substrate.In This paper we implemented recent energy-harvesting Systems which harvest energy from RF signals.
Although RF energy harvesting gives us very low power, we can power the devices which have low power requirement. In RF energy harvesting system an antenna is . Thesis or dissertation Abstract: This thesis analyses in detail the technology required for wireless power transfer via radio frequency (RF) ambient energy harvesting .
This thesis proposes a design of an RF energy harvesting device able to charge commercially available thin film or solid-state batteries. The energy harvesting amplifier circuit is designed in Global Foundry um CMOS technology using Cadence integrated circuit design tools.
for RF energy harvesting technology is the availability of adequate amount of RF power. This thesis also presents a survey of available RF power at various ultra-high frequencies in San Luis Obispo, CA.
While solar energy harvesting has been widely used for years to power remote devices, several other types of energy-harvesting approaches have also emerged for micropower applications including vibration, thermal, mechanical, and RF. A. INRF TO DC ENERGY CONVERSION The process of converting RF signal to usable form of DC voltage is performed by the Voltage Multiplication Circuit.