# Dual-Band Rectifier Circuit Design for IoT Communication in 5G Systems
## 5 Discussion  
The Fourth Industrial Revolution improved the industry model by applying digitalization to traditional industrial units. This revolution is known as \"Industry 4.0.\" The 4.0 attribute focuses on the Internet of Things (IoT) applied to industrial systems. There is an increase of over 50% per year in wireless data traffic for each user. This is estimated to accelerate over the next few years with the frequent use of video and the growth of the IoT. The wireless industry is moving to 5G cellular technology to address this phenomenon. The technological innovations the Internet of Things (IoT) brings have led to more green energy sources. IoT is a system that can transfer data over a network without requiring interaction between humans or humans and computers. One example of a green source is radio-frequency (RF) which is omnidirectional and always available. The growth of 5G has led to substantial technological innovations and the development of cutting-edge applications and services. In Frequency Zone 1 (FR1), 5G operates, among others, at the n48, n77, n78, and n79 bands. In this work, we have presented a novel dual-band rectifier circuit (discrete design) that works at frequencies of 3.5 and 5 GHz. The design methodology of this rectifier has four steps: the decision for the appropriate substrate, the selection of the circuit topology, the choice of the appropriate diode, and the design of an effective impedance-matching network. For this circuit, we need a substrate with a low dielectric constant and low dielectric loss; hence, we selected the \"RT/Duroid 5880\" substrate. Then, we designed a Greinacher voltage multiplier. In addition, for this circuit, we used the HSMS-286C diodes. To guarantee that we have a power transfer with minimum losses from the receiving  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Reference**} & \multirow{2}{*}{\ \begin{tabular}{c} **Type of** \\ **Circuit** \\ \end{tabular}  } & \multirow{2}{*}{**Substrate**} & \multirow{2}{*}{**Diode**} & \multirow{2}{*}{ \begin{tabular}{c} **Frequency** \\ **(GHz)** \\ \end{tabular}  } & & & \multicolumn{2}{c}{**PCE (\%) @**} & \\  & & & & & & & & **Desired** \\  & & & & & & & & **Frequent-** \\ \hline \multirow{3}{*}{[42]} & Half-Wave & RT/Duroid & & & & & & & **Frequent-** \\  & rectifier & 5880 & SMS-7630 & 3.5, 5.8 & 0 & 0.5 & 44 & 656.88 mV \\  & Half-Wave & & & & & & & & \\  & rectifier & & & & & & & & \\  & & & & & & & & & \\  & Full-Wave & & & & & & & &  
antenna to the rectifier, we designed an impedance-matching network with distributed elements. After finalizing the design, the \(S_{11}\) value is \(-55.335\) dB and \(-51.114\) dB at frequencies of 3.5 and 5 GHz, respectively. Furthermore, the \(S_{11}\)\(-10\)dB bandwidth (BW) is 80 MHz at 3.5 GHz and 90 MHz at 5 GHz. With an input power of 12 dBm and an output load of 2 k\(\Omega\), we achieved a PCE of 52.4% and an output voltage of 4.074 V. Lastly, this full-wave rectifier performed exceptionally well with low input power. It is notable that among the designs, the proposed circuit design is the only one that works at sub-6 GHz 5G bands and only at 3.5 and 5 GHz simultaneously. Additionally, this design can be used in several technological fields, such as military services, therapeutic, or telecommunication services. It can also be useful for different IoT applications that require energy harvesting. Energy harvesting is undeniably an excellent technique for numerous self-powered microsystems. Mobile phones, wireless sensors, remote weather stations, calculators, watches, and Bluetooth are additional examples of such systems. Numerous companies have introduced mobile phones that charge using radio frequency (RF) signals. With the rapid growth of the IoT in recent years, RF energy harvesting will play a crucial role due to the limitless nature of RF signals. Rectenna systems will be of great use in smart homes and smart cities, which are also significant new scientific fields.