High-efficiency broadband radio frequency rectifier based on double transmission lines

Abstract

The invention provides a novel broadband rectifier which integrates double transmission lines (DTL) and is applied to the field of wireless power transmission. The framework of the rectifier adopts a transmission line, the transmission line is bent into an L shape, and the transmission line and the DTL form an impedance matching network together. The DTL has the effect of counteracting the imaginary part of the diode, the rectification bandwidth is effectively widened, and the transmission line is used for impedance matching. Through experimental manufacturing and testing of the rectifier, the result shows that the conversion efficiency of the rectifier in the frequency range of 1.5-2.5 GHz exceeds 60% and the peak efficiency reaches 75.6% under the conditions that the input power is 8 dBm and the load is 1 kohm.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency (RF) environmental energy harvesting technology, specifically relating to a high-efficiency, broadband rectifier circuit employing a dual-line structure for environmental RF energy harvesting. This invention is suitable for harvesting energy from widely present RF signals in the environment and providing a sustainable power supply for low-power electronic systems such as IoT nodes, wireless sensors, wearable devices, and implantable medical devices. It consists of two Schottky diodes: diode D1 and diode D2, characterized in that: capacitor C1 is connected to TL1; the other end of C1 is connected to the diode. The anode of diode D2 is connected to the dual-line structure, and the cathode of diode D1 is connected to the common terminal of capacitors C2 and C3 and resistor RL. Background Technology

[0002] With the rapid evolution and widespread adoption of the Internet of Things (IoT) and 5G / 6G communication technologies, wireless sensor networks, as the core link between the physical world and the digital information space, have deeply penetrated into many key areas such as industrial automation, precision agriculture, environmental monitoring, smart city infrastructure, smart homes, and personal health monitoring. These systems typically consist of massive, miniaturized, distributed, low-power sensor nodes, designed to achieve real-time, continuous data acquisition and wireless transmission. However, the energy supply issue supporting the stable operation of this vast network is becoming increasingly prominent, posing a fundamental bottleneck to its large-scale, permanent deployment and sustainable development.

[0003] Traditional solutions primarily rely on disposable chemical batteries or rechargeable batteries. This approach has several insurmountable limitations: the limited energy capacity and lifespan of batteries necessitate frequent maintenance or replacement of nodes, making maintenance prohibitively expensive or even impossible for sensors deployed in remote, hazardous, or inaccessible environments (such as inside large structures, deep forests, or inside the human body); the size and weight of batteries restrict further miniaturization and flexible deployment of nodes; furthermore, the severe environmental pressure and recycling challenges caused by large quantities of discarded batteries contradict the principles of green and sustainable technological development. Therefore, developing an alternative energy solution capable of enabling devices to be self-powered or significantly extending their operational lifespan is both an urgent practical need and of significant strategic importance.

[0004] Against this backdrop, radio frequency energy harvesting technology has emerged. This technology can capture energy from radio frequency signals (such as Wi-Fi, cellular networks, and broadcast signals) that are widely present in the surrounding environment and convert them into DC power to power low-power electronic devices. This technology provides a highly promising technical path to realize "battery-free" and "maintenance-free" electronic devices, and is crucial for building a large-scale, low-maintenance, and highly autonomous Internet of Things ecosystem.

[0005] In radio frequency (RF) energy harvesting systems, the RF rectifier is a core component, converting received high-frequency AC signals into DC voltage. The rectifier's performance, particularly its power conversion efficiency and operating bandwidth, directly determines the overall system's energy utilization rate. While traditional narrowband matching networks can achieve high efficiency at specific frequencies, their bandwidth is limited. To effectively utilize RF energy distributed across different frequency bands in the environment, existing technologies often require multi-stage matching networks, complex filter structures, or distributed transmission line designs. This inevitably leads to complex circuit structures, increased size, and increased insertion loss, contradicting the urgent needs of IoT devices for miniaturization, low cost, and easy integration. Therefore, how to overcome the traditional trade-off between efficiency and bandwidth within limited or even smaller circuit dimensions to achieve a compact, high-efficiency, wide-bandwidth RF rectifier has become a key technical challenge that must be overcome to propel environmental RF energy harvesting technology from the laboratory to large-scale practical applications. It also holds significant scientific research and engineering application value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing RF rectifiers in balancing broadband performance with high efficiency and small size, and to provide a high-efficiency broadband RF rectifier based on a dual-transmission-line structure. This rectifier effectively controls the drastic changes in diode impedance over a wide bandwidth while compensating for the inherent capacitive reactance of the diode by introducing a parallel dual-transmission-line structure into the matching network. This allows for excellent broadband impedance matching with only a simple front-end transmission line, thus achieving a wide operating bandwidth while ensuring high conversion efficiency. Furthermore, the overall circuit structure is compact and small in size, making it suitable for integration into various space-sensitive low-power electronic devices. In addition, the introduction of a high-precision capacitor as a DC filter structure improves circuit stability, and the use of Schottky diodes makes it more suitable for implementation in high-frequency environments.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-efficiency broadband RF rectifier based on dual transmission lines includes: three capacitors: C1, C2, and C3; a resistor RL; dual transmission lines TL2 and TL3; transmission line TL1; and two Schottky diodes: diode D1 and diode D2. Its characteristic is that: The capacitor C1 is connected to TL1; the other end of C1 is connected to the diode. The anode of the diode D2 is connected to the double-transmission line, and the cathode of the diode D1 is connected to the common terminal of the capacitors C2 and C3 and the resistor RL.

[0008] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: the capacitor C1 is connected in series at the input terminal, and its DC blocking characteristic is used to effectively block the DC component generated by rectification from flowing back to the front stage, thereby protecting the RF signal source. The components are all cuboids with a length of 1mm, a width of 0.5mm, and a height of 0.3mm.

[0009] Furthermore, the aforementioned high-efficiency broadband RF rectifier based on dual transmission lines is characterized by: serving as an impedance adjustment element to compensate for the parasitic capacitance effect of the Schottky diode at high frequencies and suppressing the fluctuation of the diode's input impedance with frequency. By adjusting the physical dimensions of TL2 and TL3, their characteristic impedances at the operating frequency are both 117.9 Ω, and their electrical lengths are 31.5° and 49.7°, respectively. This parallel structure can effectively replace the traditional long single short-circuit transmission line, thereby reducing the circuit area.

[0010] Furthermore, in the aforementioned high-efficiency broadband RF rectifier based on dual transmission lines, after the dual transmission lines perform preliminary compensation and compression of the diode impedance, the transmission line TL1 further compresses the circuit's input impedance to a source impedance of 50 Ω, thereby achieving good impedance matching over a wide bandwidth.

[0011] Furthermore, the high-efficiency broadband radio frequency rectifier based on dual transmission lines is characterized in that the operating frequency band of the radio frequency rectifier is 1.5GHz ~ 2.5GHz.

[0012] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: when the input power is 0dBm, the RF rectifier has an RF rectification efficiency of over 40% within a bandwidth of 1.4GHz to 2.5GHz.

[0013] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: when the input power is 5dBm, the RF rectifier has an RF rectification efficiency of over 50% within a bandwidth of 1.5GHz to 2.5GHz.

[0014] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: when the input power is 8dBm, the RF rectifier has an RF rectification efficiency of over 40% within a bandwidth of 0.03GHz to 2.6GHz.

[0015] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: when the input power is 8dBm, the RF rectifier has an RF rectification efficiency of over 60% within a bandwidth of 1.5GHz to 2.5GHz.

[0016] Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: when the input power of the RF rectifier is 8dBm, and the frequency is 1.8GHz, the RF rectification efficiency is up to 75.6%.

[0017] The beneficial effects of the above-described solution in this invention are as follows: This invention utilizes a dual-line structure to enable the rectifier to operate over a wide frequency range of 0.03 GHz to 2.6 GHz, covering multiple mainstream communication frequency bands such as GSM, LTE, and Wi-Fi. Through impedance matching design, the circuit achieves an efficiency exceeding 60% in its core operating frequency band, with a peak efficiency of up to 75.6%, realizing high conversion efficiency. Simultaneously, the dual-line structure effectively reduces the physical length of the transmission lines, making it ideal for integration into size-constrained IoT sensor nodes. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the radio frequency circuit structure of the present invention.

[0019] Figure 2 This is a graph showing the conversion efficiency of the RF rectifier as a function of frequency when the input power is 0dBm in this embodiment of the invention.

[0020] Figure 3 This is a graph showing the conversion efficiency of the RF rectifier as a function of frequency when the input power is 5dBm in this embodiment of the invention.

[0021] Figure 4 This is a graph showing the conversion efficiency of the RF rectifier as a function of frequency when the input power is 8dBm in this embodiment of the invention. Detailed Implementation

[0022] The present invention will be further described in conjunction with the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown in the embodiment of the present invention, a high-efficiency broadband RF rectifier based on dual transmission lines includes: three capacitors: capacitors C1, C2, and C3; a resistor RL; a transmission line (TL1) with a length of 16 mm and a width of 0.7 mm; dual transmission lines (TL2 and TL3) with a length of 9.3 mm and a width of 0.4 mm and a length of 14.7 mm and a width of 0.4 mm, respectively; and two Schottky diodes: diode D1 and diode D2. The characteristic feature is that: The capacitor C1 is connected to TL1; the other end of C1 is connected to the diode. The anode of the diode D2 is connected to the double-transmission line, and the cathode of the diode D1 is connected to the common terminal of the capacitors C2 and C3 and the resistor RL.

[0024] To ensure the accuracy and convenience of the implementation, the impedance matching network is further constructed by consisting of a double transmission line and a transmission line TL1. The final determined impedance matching network component parameters are shown in Table 1.

[0025] Table 1 Impedance matching network parameters parameter width length TL1 0.7mm 16mm TL2 0.4mm 9.3mm TL3 0.4mm 14.7mm Furthermore, the high-efficiency broadband RF rectifier based on dual transmission lines is characterized in that: the capacitor C1 has a value of 100pF, the dielectric constant of the substrate is 2.65, the thickness is 0.8mm, the length is 21.5mm, and the width is 16.6mm.

[0026] Furthermore, the rectified voltage is passed through a DC filter structure and then connected to the load resistor RL. The final component parameters of the DC filter are shown in Table 2.

[0027] Table 2 Component parameters of DC filters parameter numerical values parameter numerical values C2 100 pF C3 100 pF Furthermore, Figure 2 The efficiency of this RF rectifier is given. As shown in the figure, the RF rectifier has an RF rectification efficiency of over 40% in the bandwidth of 1.4 GHz ~ 2.5 GHz when the input power is 0dBm.

[0028] Furthermore, Figure 3 The efficiency of this RF rectifier is given. As shown in the figure, the RF rectifier has an RF rectification efficiency of over 50% in the bandwidth of 1.5 GHz to 2.5 GHz when the input power is 5dBm.

[0029] Furthermore, Figure 4 The efficiency of this RF rectifier is given. As shown in the figure, the RF rectifier has an RF rectification efficiency of over 40% within a bandwidth of 0.03GHz to 2.6GHz when the input power is 8dBm.

[0030] Furthermore, Figure 4 The efficiency of this RF rectifier is given. As shown in the figure, the RF rectifier has an RF rectification efficiency of over 60% in the bandwidth of 1.5 GHz to 2.5 GHz when the input power is 8dBm.

[0031] Furthermore, Figure 4 The efficiency of this RF rectifier is given. As shown in the figure, the RF rectifier has a maximum RF rectification efficiency of 75.6% at an input power of 8dBm and a frequency of 1.8GHz.

[0032] Brief working principle of the invention: To achieve a compact size and wide bandwidth performance in the RF rectifier, an RF rectifier based on a dual-transmission-line (DTL) impedance matching network is employed, effectively improving the operating bandwidth and conversion efficiency. Subsequently, a voltage doubler rectification structure further enhances the output DC voltage. The core innovation of this invention lies in the introduction of a dual-transmission-line (DTL) structure. In RF rectifier design, diodes exhibit significant capacitive reactance at high frequencies, and their impedance varies greatly with frequency, making matching difficult and severely hindering efficient energy transfer. By precisely controlling the characteristic impedance and electrical length of the two branches, the same equivalent effect as a traditional long transmission line can be achieved, compressing the diode's input impedance trajectory into a very small region with a near-zero imaginary part, while simultaneously enabling a smaller physical size. This greatly simplifies the design of the front-end matching network, allowing broadband matching to be achieved with only a simple transmission line TL1.

Claims

1. A high-efficiency broadband radio frequency rectifier based on dual transmission lines, comprising: Three capacitors: C1, C2, and C3; one resistor RL; a transmission line (TL1) 16 mm long and 0.7 mm wide; two double transmission lines (TL2 and TL3) 9.3 mm long and 0.4 mm wide and 14.7 mm long and 0.4 mm wide, respectively; two Schottky diodes: diode D1 and diode D2, characterized in that: capacitor C1 is connected to TL1; the other end of C1 is connected to the diode. The anode of diode D2 is connected to the double transmission line, and the cathode of diode D1 is connected to the common terminal of capacitors C2 and C3 and resistor RL.

2. The high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The DC component is isolated by capacitor C1, and all components are cuboids with dimensions of 1 mm in length, 0.5 mm in width, and 0.3 mm in height.

3. The high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The impedance matching network consists of two parallel transmission lines, TL2 and TL3, which have a characteristic impedance of 117.9Ω at the operating frequency. The electrical lengths of TL2 and TL3 are 31.5° and 49.7°, respectively.

4. The high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The operating frequency band of the radio frequency rectifier is 1.5GHz~2.5GHz.

5. A high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The RF rectifier has an RF rectification efficiency of over 40% within a bandwidth of 1.4GHz to 2.5GHz when the input power is 0dBm.

6. The high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The RF rectifier has an RF rectification efficiency of over 50% within a bandwidth of 1.5GHz to 2.5GHz when the input power is 5dBm.

7. A high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The RF rectifier has an RF rectification efficiency of over 40% within a bandwidth of 0.03GHz to 2.6GHz when the input power is 8dBm.

8. A high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: The RF rectifier has an RF rectification efficiency of over 60% within a bandwidth of 1.5GHz to 2.5GHz when the input power is 8dBm.

9. A high-efficiency broadband RF rectifier based on dual transmission lines according to claim 1, characterized in that: When the input power of the RF rectifier is 8dBm and the frequency is 1.8GHz, the RF rectification efficiency is up to 75.6%.

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