International Journal of Pure and Applied Mathematics Volume 119 No. 16 2018, 3479-3484 ISSN: 1314-3395 (on-line version) url: http://www.acadpubl.eu/hub/ Special Issue http://www.acadpubl.eu/hub/ RF Energy Harvesting Using Rectenna Srikanth S1 Beulah Jackson 2 Manju Bagavathy J 3 Asst.Prof1 Professor 2 Student 3 Department of Electronics and Communication Engineering123 Loyola ICAM College of Engineering and Technology 13 Saveetha Engineering College 2, Chennai, Tamil Nadu, India. [email protected] [email protected] 2 [email protected] Abstract— This paper introduces a rectenna utilizing microstrip Keeping in mind the end goal to catch the RF control however innovation that can collect the accessible RF vitality display in much as could reasonably be expected, microstrip antennas are the air for serving applications like powering the remote sensors connected as the receiving segments of the rectennas. which are out of reach to people. The novel rectenna outlined Likewise, a high-effectiveness rectifier is planned and after works at a recurrence of 2.4 Ghz with a gain of 4.186dB. The that joined with the reception apparatus as the proposed rectifier utilized is a Schottky diode HSMS-2850, which is used for changing over the RF AC to DC control. Estimations rectenna. This overall with the resistor towards the end creates demonstrate that a yield of 328mV was acquired over a 5KΩ a DC voltage of 328mV to control the sensors. The rectenna's resistor for a contribution of 707mV, which was figured from a execution is checked by both simulation and test results. Wi-Fi gadget whose return loss was observed to be 20dBm. The bandwidth achieved is from 2.37GHz to 2.45 Ghz. Keywords— Rectenna, RF energy harvesting. I. INTRODUCTION RF energy harvesting[REH] has as of late turned into a II. RECTENNA DESIGN prominent research subject because of its various applications [1]. RF vitality is communicated from various purposeful or A. Antenna Element Design accidental electromagnetic assets [2], [3], for example, GSM- Due to the research project related requirements, the 900, GSM-1800, Wi-Fi(2.4Ghz), 3G et cetera. With this rectenna is intended to collect the RF power from the 2.4-GHz availability to free Wi-Fi vitality the REH innovation can Wi-Fi band. The two sections of the rectenna, including possibly introduce another age of the self powered gadgets. antenna and the rectifier, are composed independently. The In a REH framework, the key part is the rectenna, which antenna component is appeared in Fig. 1, which is imprinted gathers the RF energy and after that converts it into DC on two FR4(lossy) substrate with thickness of 1.6mm and control for the utilization of the back-end gadgets. A short relative dielectric constant of 4.33. It is optimized at the centre history of radio power transmission has been compressed in frequency of 2.4 GHz. Its deliberate 20-dB return-loss data [4]. Lately numerous endeavours have been given to the transmission is from 2.37 to 2.45 GHz. This antenna outline of rectennas from various viewpoints. In [5], a double component will be used to frame the rectenna. band rectenna is planned in order to gather more power from Microstrip antenna is one of the most popular types of printed various groups. As the information control levels could be low antenna. It plays a very significant role in today’s world of in some REH applications, the efficiencies of rectennas under wireless communication systems. Microstrip antennae are very low info control conditions have been talked about and simple in construction using a conventional microstrip streamlined in points of interest in [6]. Other than surrounding fabrication technique. The numerous advantages of microstrip REH rectennas [2], [5] have been examined also. All the past antenna, such as its low weight, small volume, and ease of research endeavours have propelled the REH innovation to an fabrication using printed- circuit technology, led to the design abnormal state of development. of several configurations for various applications. With increasing requirements for personal and mobile communications, the demand for smaller and low-profile 3479 International Journal of Pure and Applied Mathematics Special Issue antennas has brought the microstrip antenna to the forefront. A microstrip antenna in its simplest form consists of a radiating patch on one side of a dielectric substrate and a ground plane on the other side as shown in Figure 1. The patch is made of a conducting material generally copper on the substrate. The patch thickness is of 0.036mm, fabricated on top of the substrate FR4, which is placed over the ground Microstrip antennas are increasing in popularity for use in wireless applications due to their low-profile structure, therefore they are extremely compatible for embedded antennas in handheld wireless devices. The telemetry and communication antennas on missiles are often in the form of microstrip patch antennas. For effective radiation width of the patch is given by Bahl and (Fig 1) Top view of the proposed antenna Bhartia as w=(v0/2fr) (2/ℇr+1) B. Matching Network and Rectifier The effective dielectric constant is given by Balanis as, In order to achieve maximum power transfer, we need to ℇ = (ℇ +1/2) + (ℇ -1/2) match the impedance of the load to that of the source. Usually reff r r this is done by incorporating additional passive networks − / connected in between source and load. These networks are [1 + 12(h/w)] ퟏ ퟐ generically referred to as matching networks. The whole topology of the proposed rectifier is illustrated in Fig. 5. The where ℇ =effective dielectric constant reff substrate utilized is 1.6mm thick with dielectric constant of ℇ =dielectric constant of substrate r 4.33. In this outline, the series-mounted diode topology is h=height of the substrate adopted since it has a tendency to have a higher productivity w=width of the patch under low-input RF control conditions [7]. As appeared in Fig. 6(a) from TL1 to TL6, a two-segment T-shape microstrip The extension of length of the patch is determined using the transformer [8] is utilized to improve the band width and the equation by Hammerstad as, optimized widths of the microstrip lines are not very wide or excessively thin. To give a dc-patch in the circuit, the ΔL= 0.412h [(ℇ + 0.3) (w/h+ 0.264)/( ℇ + 0.258)(w/h + reff reff microstrip line TL6 is grounded by means of holes. 0.8)] A Schottky diode Avago HSMS-2852 (Vth=150mV, Cj=0.18pF, Rs=25Ω ) is inserted between the matching circuit To calculate the effective length of the patch for given and the dc-pass filter to convert the microwave power into dc operating power. The dc-pass filter is realized by a simple stepped- frequency fr, impedance microstrip line low-pass filer, followed by a resistive load to extract the dc power. Leff =(c/2fr)(1/ ℇreff) The parameters of the matching circuit, dc-pass is used and, filter, and the resistive load can be initially calculated and then optimized in the software Computer Simulation Technology Leff = L+ΔL (CST) by setting appropriate goals. At the first stage, a Hence actual length of the patch is found by, preliminary rectifier containing only a diode, a dc-pass filter, and a resistor was optimized under low input power with the L= Leff − 2ΔL goal of high efficiency at 2.4 GHz. In this way, the optimal dc- pass filter and the load resistance was obtained. After that, the In this design of antenna we find the return loss, gain matching circuit was optimized separately to match the input and band width of the antenna. The dimensions of the antenna impedance of the rectifier to 50 at 2.4 GHz. includes lg= 49.5mm, lp=30mm, wg=47.6363mm, The optimized parameters are w1=3.13mm wp=38.03mm, x=3mm and y=7mm, where x and y is the ,l1=22mm ,w2=14mm ,l2=22mm, w3=2mm, l3=13.3, length and width of the notch created. w4=3,l4=25.3mm, w5=0.978mm, l5=17mm, w6=9mm, The antenna designed is shown in the figure 3 along with l6=19.5mm .The load resistance is 5 k. The output impedance the test results (figure 4) and simulation results (figure 2). The at the end point is 89.14 ohms. To get the refined output, test results prove that we have obtained a return loss of 20dB transmission line 6 is grounded. The simulation result shows at the operating frequency of 2.4Ghz. an insertion loss of -2.21dB and a return loss of -22.56dB. 3480 International Journal of Pure and Applied Mathematics Special Issue This conveys nearly 50% of the power has been transferred In this design the rectifier used is hsms 2850 which from the antenna to the diode. converts the input RF power into DC power. The matching Fig 6 shows the top view of the simulated matching network and filter are combined and shown in the figure 5. It network. Analysing the measured return losses of the rectifier has an operating voltage of 150mV at 2.4Ghz. The equivalent along with the insertion loss, it can be found that good circuit of the diode was obtained from the data sheet and this impedance matching is achieved at 2.4 GHz, proving was simulated using a software LT Spice as shown in fig 6. the capability of the matching circuit. Fig.2 Simulated reflection coefficients of the proposed antenna Fig 5 Top view of the matching network The simulation results of the matching network in LT Spice is shown in the figure8.