A compact rectangular slotted antenna fed through coplanar waveguide for rectenna system is proposed in the application of radio frequency (RF) energy harvesting at center frequency of 2.45 GHz in the wireless local area network (WLAN) band. Three unequal widths of rectangular slots with equal distance have been created step by step to maximize the peak gain to 3.6 dB of the antenna. Radiation plot of the proposed antenna has been depicted to be omnidirectional for RF energy harvesting with maximum radiation efficiency characteristics. The dimension of the antenna is reduced up to 28 × 17 mm2 with better reflection coefficient of -34.6dB.
TopIntroduction
With the growth in technology, RF wireless energy harvesting (WEH) has been receiving an extensive research approaches by the researchers for the human welfare. It has the potential to harvest more energy from the various RF energy sources, for example Wi-Fi, WLAN, portable devices etc. Through the use of Internet of Things (IoT) number of users can be connected freely. Battery consuming more power as the number of usages increases by the users then RF energy harvesting come in the environment. The wireless energy harvesting ideas have been prolonged for more than last two decades. Different ambient energy sources are available for energy harvesting such as vibration energy sources (approx. 200µW/cm2), solar energy (approx. 100mW/cm2), RF energy (approx. 1µW/cm2) and thermal energy (approx. 60µW/cm2). The wireless power transfer (WPT) divided in two parts: transmitter and receiver. The receiving part is the RF WEH and has received extensive growth in the last decades.
RF energy harvesting is useful in the unfavorable applications such as health monitoring, environment monitoring, defense, surveillance etc. in (Bhatt et al., 2019)-(Vu et al., 2020). Rectenna system design is used for RF WEH. It comprises of antenna may be a microstrip antennas or any other, rectifying circuit composed of capacitor, inductor and low threshold diode which is used to change the RF wave to Direct current (DC) and storing devices are introduced in the literature by various energy sources that influenced by various environmental factor but RF energy sources independent of these factors in (Danesh & Long, 2011)-(Bito et al., 2017). RF broaden the range of frequencies in telecommunication area such as industrial, scientific and medical (ISM) band, Universal Mobile Telecommunication Service (UMTS) 2.1GHz, 1.8GHz (GSM) and WLAN (2.4GHz, 5.8GHz) in (Sun et al., 2013),(),(Elwi et al., 2019).
Figure 1. Block diagram of wireless energy harvesting system.
In this, the proposed antenna used to receive energy from various RF sources and rectifying circuit converts it into direct current (DC) from electromagnetic wave with high efficiency at different compact rectenna with single wide band high efficiency is frequencies, DC filter applied after it to smoothen the DC waveform and then some devices is used to store. A being discussed in (Sun et al., 2012)-(Takhedmit, 2010) and slotted microstrip patch antenna with dual band for WLAN has antenna used to receive energy from various RF sources and rectifying circuit converts it into direct current (DC) from electromagnetic wave with high efficiency at different frequencies, DC filter applied after it to smoothen the DC waveform and then some devices is used to store. A compact rectenna with single wide band high efficiency is being discussed in (Sun et al., 2012)-(Takhedmit, 2010) and slotted microstrip patch antenna with dual band for WLAN has reported in (Khemar et al., 2018)-(Heikkinen & Kivikoski, 2003), then for triple band rectenna (Chandravanshi et al., 2018),(Liu & Zhang, 2018), Quadband rectifier (Hsu et al., 2017), six band (Song et al., 2016), multiband planar antenna (Nimo et al., 2012), Frequency tunable energy harvesting rectenna (Song et al., 2017), broadband rectenna (Nie et al., 2015).
In this paper, the proposed antenna has been designed and simulated in section II, results have been discussed in section III and then at last conclusion is proposed.