A radio frequency rectifying circuit with a hybrid short circuit stub

Abstract

The application discloses a kind of mixed short-circuit stubs radio frequency rectifier circuit, specifically includes, first capacitor;Second capacitor;First terminal short-circuit transmission line, the series connection second capacitor, first diode is passed through the first terminal short-circuit transmission line and is grounded;The length of first terminal short-circuit transmission line is;First terminal short-circuit transmission line is used for fundamental wave matching and inhibits second harmonic;Second terminal short-circuit transmission line, the series connection first capacitor, second diode is passed through the second terminal short-circuit transmission line and is grounded;The beneficial effects of the application are that the circuit innovatively introduces two different electric lengths of terminal short-circuit transmission line, can realize impedance matching of fundamental frequency and harmonic suppression recovery simultaneously, only needs to adjust the characteristic impedance of two short-circuit lines, namely, impedance matching in wide input power range and wide load resistance value range can be realized, greatly simplifies matching adjustment process, effectively reduces circuit size simultaneously, realizes the miniaturization of circuit.

Description

Technical Field

[0001] This invention belongs to the field of rectifier circuit technology, and specifically relates to an RF rectifier circuit based on a hybrid short-circuit stub of λ / 8 and λ / 12. Background Technology

[0002] As a key component in wireless power transmission, RF power harvesting, and microwave power transmission systems, the performance of the RF rectifier circuit directly determines the energy conversion efficiency of the entire system. A traditional RF rectifier circuit typically consists of four parts: an input matching network, rectifier diodes, a low-pass filter, and a load. The input matching network often employs an LC network or a single-length transmission line structure to achieve impedance matching between the RF source and the rectifier circuit at a specific operating point.

[0003] However, existing technologies have significant limitations: First, the input matching network of traditional rectifier circuits is usually optimized for specific input power and fixed load. When the input power or load resistance changes significantly, the impedance matching condition is disrupted, leading to a sharp drop in rectification efficiency. Second, the harmonic handling mechanism in conventional designs is imperfect, and the high-order harmonic components generated by the diodes cannot be effectively suppressed and recovered, resulting in energy waste. Third, to achieve a wide range of impedance matching, existing solutions often require the design of complex multi-stage matching networks, which not only increases the complexity of the circuit but also significantly increases the circuit area, hindering the miniaturization and integration of the system.

[0004] Therefore, the industry urgently needs a new type of RF rectifier circuit topology that can effectively broaden the dynamic range of input power and the load adaptability range while ensuring high conversion efficiency, simplify the matching and adjustment process, reduce the circuit size, and provide a more efficient, compact and adaptable solution for wireless power transmission systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hybrid short-circuit stub radio frequency rectifier circuit, which utilizes the typical structure of a radio frequency rectifier circuit, specifically including:

[0006] First capacitor; Second capacitor;

[0007] The first terminal short-circuit transmission line is connected to the ground via the second capacitor and the first diode in series; the length of the first terminal short-circuit transmission line is λ / 8; the first terminal short-circuit transmission line is used for second harmonics.

[0008] The second terminal short-circuit transmission line is connected in series with the first capacitor and the second diode, and grounded through the second terminal short-circuit transmission line; the length of the second terminal short-circuit transmission line is λ / 12; λ is the wavelength.

[0009] An upper branch is provided between the first capacitor and the second diode, wherein the upper branch is the first capacitor connected in series with the first inductor and connected to one end of the load; and a first grounding capacitor is connected in parallel between the first inductor and the load.

[0010] A lower branch is provided between the second capacitor and the first diode. The lower branch is a second capacitor connected in series with a second inductor and connected to the other end of the load. A second grounding capacitor is connected in parallel between the second inductor and the load.

[0011] The output low-pass filter circuit of the aforementioned RF rectifier circuit is a low-pass filter with a cutoff frequency lower than the fundamental frequency of the input signal. Its function is to allow the rectified DC signal to pass through and reflect the high-order harmonic components generated by the diodes. The DC load, together with the low-pass filter and the rectifier diodes, forms a complete DC path.

[0012] Furthermore, both the first diode and the second diode are Schottky diodes, taking advantage of the characteristics of Schottky diodes such as high cutoff frequency, low forward voltage, and high switching speed.

[0013] Furthermore, both the first capacitor C1 and the second capacitor C2 are DC blocking capacitors.

[0014] Furthermore, the positive terminal of the first diode D1 is connected to the first terminal short-circuit transmission line L1, and the negative terminal of the first diode D1 is connected to the second capacitor C2.

[0015] Furthermore, the positive terminal of the second diode D2 is connected to the first capacitor C1, and the negative terminal of the second diode D2 is connected to the second terminal short-circuit transmission line L2.

[0016] The aforementioned RF rectifier circuit comprises four parts: a matching circuit, a rectifier diode, an output low-pass filter circuit, and a DC load. The input matching circuit typically employs a passive network configuration, exhibiting bandpass characteristics. Its core function is to achieve impedance matching between the RF source and the rectifier circuit at the fundamental frequency, while simultaneously preventing high-order harmonics generated by the rectifier diode from entering the RF source. The rectifier diode, with its unidirectional conduction characteristic, is the core component for RF-to-DC energy conversion.

[0017] The beneficial effects of this invention are that the circuit innovatively introduces two types of terminal short-circuit transmission lines with different electrical lengths, which can simultaneously achieve impedance matching of the fundamental frequency and suppression and recovery of harmonics. Only the characteristic impedance of the two short-circuit lines needs to be adjusted to achieve impedance matching in a wide range of input power and a wide range of load resistance, which greatly simplifies the matching adjustment process and effectively reduces the circuit size, thus realizing the miniaturization of the circuit.

[0018] Compared to traditional rectifier circuits, this design offers a wider range of input power and load variations while ensuring high-efficiency energy conversion, providing a miniaturized, high-efficiency, and highly adaptable rectifier circuit structure for wireless power transmission systems. Attached Figure Description

[0019] Figure 1 Circuit structure diagram of an embodiment of the present invention;

[0020] Figure 2 Comparison of input impedance and |S11| simulation results between the dual λ / 8 structure and the hybrid λ / 8 and λ / 12 structure in this invention embodiment;

[0021] Figure 3 The rectifier circuit layout and physical diagram of this invention are shown in the embodiments.

[0022] Figure 4 The efficiency of the rectifier circuit in this embodiment of the invention varies with the input power;

[0023] Figure 5 The output voltage of the rectifier circuit in this embodiment of the invention varies with the input power;

[0024] Among them, the first capacitor C1; the second capacitor C2; the first terminal short-circuit transmission line L1; the first diode D1; the second terminal short-circuit transmission line L2; the second diode D2; the first grounding capacitor C3; the first inductor l1; and the second inductor l2. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] An embodiment of the present invention provides an RF rectifier circuit based on a hybrid short-circuit stub of λ / 8 and λ / 12, where λ is the wavelength. Specifically, it includes a first terminal short-circuit transmission line L1, wherein the series-connected second capacitor C2 and the first diode D1 are grounded through the first short-circuit transmission line L1; the length of the first short-circuit transmission line L1 is λ / 8.

[0028] The second terminal short-circuit transmission line L2, the series first capacitor C1 and the second diode D2 are grounded through the second short-circuit transmission line L2; the length of the second short-circuit transmission line L2 is λ / 12; wherein, the first diode D1 and the second diode D2 are both Schottky diodes.

[0029] An upper branch is formed between the first capacitor C1 and the second diode D2. The upper branch consists of the first capacitor C1 connected in series with the first inductor L1 and connected to the load R. L One end; the first inductor l1 and the load R L The first grounding capacitor C3 is connected in parallel between them;

[0030] A lower branch is formed between the second capacitor C2 and the first diode D1. The lower branch is formed by connecting the second capacitor C2 in series with the second inductor L2 and then connecting it to the load R. L The other end; the second inductor l2 and the load R L A second grounding capacitor C4 is connected in parallel between them.

[0031] Preferably, the positive terminal of the first diode D1 is connected to the first terminal short-circuit transmission line L1, and the negative terminal of the first diode D1 is connected to the second capacitor C2.

[0032] Preferably, the positive terminal of the second diode D2 is connected to the first capacitor C1, and the negative terminal of the second diode D2 is connected to the second terminal short-circuit transmission line L2.

[0033] Experimental Example

[0034] Based on the characteristics of the above-mentioned rectifier circuit structure, the present invention provides a rectifier circuit topology that combines wide power and wide load range, such as... Figure 1 As shown, the first terminal short-circuit transmission line L1, the series second capacitor C2 and the first diode D1 are grounded through the first short-circuit transmission line L1; the length of the first short-circuit transmission line L1 is λ / 8;

[0035] The second terminal short-circuit transmission line L2 is used to connect the series first capacitor C1 and the second diode D2 to ground. The length of the second terminal short-circuit transmission line L2 is λ / 12. The first diode D1 and the second diode D2 are both Schottky diodes.

[0036] An upper branch is formed between the first capacitor C1 and the second diode D2. The upper branch consists of the first capacitor C1 connected in series with the first inductor L1 and connected to the load R. L One end; the first inductor l1 and the load R L The first grounding capacitor C3 is connected in parallel between them;

[0037] A lower branch is formed between the second capacitor C2 and the first diode D1. The lower branch is formed by connecting the second capacitor C2 in series with the second inductor L2 and then connecting it to the load R. L The other end; the second inductor l2 and the load R L A second grounding capacitor C4 is connected in parallel between them.

[0038] The structure adopts a dual-diode parallel architecture. The λ / 8 and λ / 12 terminal short-circuit transmission lines are connected in series with the corresponding diodes to compensate for their own capacitive reactance. Among them, the first capacitor C1 and the second capacitor C2 are both DC blocking capacitors. The first inductor l1 and the first grounding capacitor C3, and the second inductor l2 and the second grounding capacitor C4 respectively form two output low-pass filters.

[0039] To verify the feasibility of this topology, the circuit structure was further analyzed, and a rectifier circuit operating at a frequency of 2.45 GHz was designed. The input impedances of the λ / 12 transmission line of the second-terminated short-circuited transmission line L2 under DC, fundamental frequency, and high harmonic conditions are as follows:

[0040]

[0041] Z1 is the characteristic impedance of the short-circuited transmission line at the termination.

[0042] Similar to the λ / 8 terminated short-circuit transmission line of the first terminated short-circuit transmission line L1, the λ / 12 terminated short-circuit transmission line L2 provides a DC path in DC mode; compensates for the capacitive impedance of the diode at the fundamental frequency; and presents high impedance at the third harmonic to achieve harmonic suppression and power recovery.

[0043] When the input power is 25dBm and the load resistance is 400Ω, the input impedance of the HSMS-282C diode at the base frequency is:

[0044]

[0045] Assuming the impedance of both short-circuited transmission lines is Z0 = 125Ω, the inductive reactance provided by the λ / 8 short-circuited stub and the λ / 12 short-circuited stub to the corresponding diodes at the fundamental frequency are as follows:

[0046]

[0047] Based on the above parameters, the overall input impedance of the circuit after the two diodes are connected in parallel can be calculated as follows:

[0048]

[0049] This impedance value is very close to the standard source impedance of 50Ω, achieving good matching without the need for an additional matching network. Using two short-circuited transmission lines provides differentiated inductive reactance compensation, allowing the two parallel diodes to exhibit weak capacitive and inductive characteristics respectively, thus satisfying the source impedance matching condition over a wider operating range.

[0050] like Figure 2 As shown, the impedance matching performance of the two transmission line architectures is compared within the input power range of 0dBm to 30dBm. The results show that the input impedance distribution of the circuit under the hybrid λ / 8 and λ / 12 structures is more concentrated around 50Ω; simultaneously, it meets the good matching condition (|S... 11 The input power range of (<-10dB) is also significantly widened, further verifying the matching advantages of the hybrid topology in achieving wide power and wide load in the embodiments of the present invention.

[0051] Based on the above analysis and design, this embodiment of the invention completed the physical fabrication and performance verification of a rectifier circuit with an operating frequency of 2.45 GHz. The circuit substrate is an F4B high-frequency board with a dielectric constant of 2.65, a loss tangent of 0.002, a thickness of 1 mm, and a copper plating thickness of 35 μm. The diode used is an HSMS-282C. The completed circuit is shown below. Figure 3 As shown.

[0052] The results are as follows Figure 4 As shown, with a fixed input power frequency of 2.45 GHz, the rectification efficiency as a function of input power was tested under different load resistances. The curves showing the output DC voltage versus input power under different load resistances are also presented. As can be seen from the figure, at lower input power, the DC voltage increases slowly and remains below 3V; when the input power exceeds 15 dBm, the DC voltage rises rapidly with increasing input power, reaching a maximum of 16V at an input power of 30 dBm and a load resistance of 500 Ω. The measured and simulated curves for different load resistances show little difference, with a significant difference only appearing when the input power is greater than 25 dBm. This is due to the difference between the diode simulation model and the actual device under high power conditions.

[0053] like Figure 5As shown, the rectification efficiency reaches its maximum value of 81.1% when the input power is between 20 and 25 dBm. Different load resistance values ​​have little impact on the test results, with better efficiency performance under 300Ω and 400Ω loads. Within the input power range of 16–26 dBm, the rectification efficiency is greater than 70%; when the input power is widened to 13–30 dBm, the rectification efficiency remains above 60%. Compared to conventional rectifier circuits, this circuit can achieve high rectification efficiency over a wider input power range.

[0054] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A radio frequency rectifier circuit with hybrid short-circuit stubs, characterized in that, include: First capacitor; Second capacitor; The first terminal short-circuit transmission line is connected to ground via the second capacitor and the first diode, which are connected in series through the first terminal short-circuit transmission line; the length of the first terminal short-circuit transmission line is [length missing]. ; The second terminal short-circuit transmission line is used to connect the first capacitor and the second diode in series to ground; the length of the second terminal short-circuit transmission line is [length missing]. Where λ is the wavelength; An upper branch is provided between the first capacitor and the second diode. The upper branch consists of the first capacitor connected in series with the first inductor and connected to one end of the load. A first grounding capacitor is connected in parallel between the first inductor and the load. The positive terminal of the second diode is connected to the first capacitor, and the negative terminal of the second diode is connected to the second terminal short-circuit transmission line. A lower branch is provided between the second capacitor and the first diode. The lower branch consists of the second capacitor connected in series with the second inductor and connected to the other end of the load. A second grounding capacitor is connected in parallel between the second inductor and the load. The positive terminal of the first diode is connected to the first terminal short-circuit transmission line, and the negative terminal of the first diode is connected to the second capacitor.

2. The RF rectifier circuit with hybrid short-circuit stubs according to claim 1, characterized in that, Both the first diode and the second diode are Schottky diodes.

3. The RF rectifier circuit with hybrid short-circuit stubs according to claim 1, characterized in that, Both the first capacitor C1 and the second capacitor C2 are DC blocking capacitors.

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