Search

This paper presents a slotline open-loop resonators based frequency reconfigurable antenna with autonomous switching of frequency bands. The dual-port slot antenna is designed to operate at 2.1 GHz when excited at port-1, and when port-2 is excited, the antenna can be reconfigured to operate at 2.85 GHz and 5.52 GHz, respectively. Port-1 is used to receive the control signal, which is converted to a DC signal using a rectifier. The rectified control signal is used to switch the operating frequency bands of the port-2. The proposed antenna configuration gives the flexibility of remote/wireless control of the operating frequency. The antenna prototype is fabricated and measured for observing the frequency switching at port-2. The measured results show that the antenna has been effectively switched from lower band frequency (2.8 GHz) to upper band frequency (5.41 GHz) when the PIN diode is ON. The proposed antenna in its final configuration can be potentially suitable for transmitter reconfigurable antenna without the need for external DC bias voltage.

In this paper, three compact, high-efficiency, gain enhanced antennas, and corresponding rectifiers have been proposed for GSM1800, 3G, and 4G-LTE energy harvesting applications. The inverted L-stub is placed on the ground plane of the monopole antenna to get the desired frequency band of GSM1800 MHz. The feed length variation method has been adopted for the slot antennas to obtain the required frequency of 3G and 4G-LTE cellular bands. The performance of antennas is analyzed with the inverted L-stub, feed length variation, and the reflector distance. The maximum gain achieved with the reflector positioned at a distance of λ/4 from the antenna backside is three times greater than the gain obtained without the reflector. The prototype antennas and rectifiers have been simulated, fabricated, measured various parameters, and compared with the simulation results. The antennas provide more than 82% radiation efficiency and an enhanced gain of greater than 5.6 dB. The peak efficiency of rectifiers of more than 30% has been achieved. The aforementioned three antennas are integrated with their corresponding rectifiers for operating at 1.8, 2.1, and 2.3 GHz frequencies. The proposed rectennas are formidably suitable for the reception of RF power from the cellular bands.

A tri-band symmetrically truncated modified square slot antenna with enhanced gain integrated with a triple-band rectifier for low-power RF energy harvesting applications is presented in this paper. The antenna triple bands of 1.9 GHz, 3.1 GHz, and 6.4 GHz are obtained by coupling the slot with an optimized microstrip feed line length of 37 mm. To enhance the realized gain, a full copper patch reflector size greater than the antenna size is positioned in the bottom of the antenna at a distance of $\lambda/4$ . where $^{\prime}\lambda^{\prime}$ is free space wavelength at the lowest frequency of 1.9 GHz. A single diode series-configuration-based triple-band rectifier along with an impedance matching network is designed at the aforementioned similar frequencies of the antenna. The designed prototypes are fabricated, measured the essential parameters, and compared with the simulation results. The measurement results show that the enhanced gains of the antenna are 4.8 dB, 6.7 dB, and 8.9 dB obtained at the corresponding frequencies, and the rectenna peak conversion efficiency reached 27% at an optimized values of 1 KΩ load resistance and −5 dBm input power. The proposed triple-band rectenna is found to be suitable for low-power RF energy harvesting and wireless power transfer applications.

A dual-band differential fractal slot antenna with enhanced gain for RF energy harvesting applications has been proposed in this paper. The antenna is designed to operate in frequency bands of UMTS (2.1 GHz), and WiMAX (3.3–4.1 GHz). The reflector directs the radiation in the forward direction, which results in an improvement in the gain, impedance matching, and reflection coefficient bandwidth of the two bands. The proposed antenna is designed, fabricated, and the results of the simulation and measurement are compared. The theoretical analysis of the proposed antenna is also carried out. The maximum gain of the antenna with the reflector at 2.18 GHz and 3.72 GHz frequency is more than 6 dBi. The antenna radiation efficiency of 62% and 84% are obtained for the UMTS and the WiMAX bands of operation, respectively.

A dual-band planar rectenna, consisting of a modified quadrilateral square slot antenna with rectangular microstrip patch connect to a 50 Ω feed line to improve the impedance matching and a single-series diode configuration-based half-wave rectifying circuit for high conversion efficiency, operate in frequency bands of universal mobile telecommunication service UMTS (2.1 GHz) and higher WLAN/Wi-Fi (5 GHz), is proposed for RF energy harvesting and wireless power transmission. The inverted L-section transmission line is introduced between the diode and dc pass filter to eliminate the harmonics within the operating frequencies. The antenna is connected to the rectifying circuit by using a pair of 50 Ω SMA coaxial connectors. The peak measured conversion efficiency of proposed rectenna is 59.4% achieved at the input power of −9.8 dBm and optimized load resistance of 560 Ω, respectively.

In this paper, a compact dual-band rectenna operating in the frequency range of 4.8-5.2 GHz (Wi-Fi) and 7.77.9 GHz has been proposed. The antenna dual-band is achieved at a feed length of 38 mm by varying the feed length. The dual-band rectifier is designed with the help of Villard voltage doubler circuit with single T-matching network. The proposed rectenna has been implemented by integrating the rectifier to the antenna. The simulation results of antenna, rectifier, and rectenna are performed individually. The antenna is fabricated, various parameters measured, and compared with the simulated results. The maximum measured power conversion efficiency (PCE) of rectifier and rectenna of 51.7 % and 48.5% have been obtained.

In this paper Quatrefoil shape CPW-Fed monopole antenna and slot antenna operating at GSM1800 MHz and UMTS2.1 GHz cellular bands are proposed. Simulated results show that the radiation efficiency of CPW fed monopole antenna and slot antenna at GSM1800 MHz and UMTS2.1 GHz are 93% and 81% respectively. Similarly the realized gains of monopole antenna and slot antenna operating at GSM1800 MHz and UMTS 2.1 GHz are 2.49 dB and 2.2 dB respectively.