SINGLE-SOURCE MICROWAVE HEATING DEVICE

Abstract

A single-source microwave heating device comprises a first power divider, a microwave emitter module, and a phase-shift channel. An input port and an isolated port are located on one side of the first power divider. Two output ports are located on opposite sides of the first power divider. The microwave emitter module is connected to the input port. The first power divider splits the microwaves from the microwave emitter module between the two output ports. Each end of the phase-shift channel is connected to one of the two output ports. A first phase-shift module and a standing-wave heating chamber are mounted in series along the phase-shift channel.The phase shift provided by the first phase-shift module varies according to the position of the first phase-adjustment assembly, so that the positions of the standing wave crests in the standing wave heating chamber can be moved back and forth to achieve uniform heating.

Description

SINGLE-SOURCE MICROWAVE HEATING DEVICE Background of the invention Field of invention The present invention relates to a heating device that uses microwaves, in particular, it relates to a standing wave type microwave heater. Description of the related technique Conventional microwave heaters fall into two main groups: standing-wave microwave heaters and wandering-wave heaters. Standing-wave microwave heaters have a resonant chamber where microwaves resonate to form standing waves. The object to be heated is placed in or passes through the resonant chamber, where it absorbs microwave energy and is heated. However, the standing waves create hot and cold spots that are fixed in space within the resonant chamber, making it difficult to heat the object evenly. Wandering wave heaters do not create significant hot and cold spots, and therefore, they can heat materials with low microwave absorption evenly. However, when heating materials with high microwave absorption, microwave energy is absorbed by the portion of the object closest to the microwave emitter, leaving the portion farther away insufficiently heated. In short, conventional traveling wave heaters cannot yet achieve uniform heating. Brief description of the invention The main objective of the present invention is to provide a single-source microwave heating device, in which a standing wave is formed in a microwave channel conventionally used to propagate traveling waves and the positions of the hot spots originating from the standing wave can be controlled to achieve uniform heating. A single-source microwave heating device is configured to heat the object to be heated. The single-source microwave heating device comprises a first energy divider, a microwave emitter module, and a waveform switching channel. The first energy divider has one input port, one isolated port, and two output ports. Two opposite sides of the first energy divider are an input side and an output side, respectively. The input port and the isolated port are located on the input side, and the two output ports are located on the output side. The microwave emitter module is configured to emit a microwave toward the first energy divider through the input port. The first energy divider splits the microwave from the microwave emitter module between the two output ports according to a The first phase-shifting module (QLbLnn / cznz / e / Yi) is a primary splitter and emits split microwaves from the two output ports. Each of the two opposite ends of the phase-shifting channel is connected to one of the two output ports of the first phase-shifting module. A first phase-shifting module and a standing-wave heating chamber are located in series along the phase-shifting channel. The first phase-shifting module is configured to change the phase of a microwave passing through it. The first phase-shifting module has a first phase-adjustment assembly and a first drive assembly. The phase shift provided by the first phase-shifting module varies according to the position of the first phase-adjustment assembly. The first drive assembly controls the position of the first phase-adjustment assembly.The standing wave heating chamber is configured to accommodate the object to be heated. Microwaves emitted from the two output ports of the first power divider interfere to form a standing wave in the switching wave channel. The positions of the standing wave crests in the switching wave channel vary according to the position of the first phase-adjustment assembly. The standing wave in the switching wave channel is absorbed by the object to be heated in the standing wave heating chamber. A single-source microwave heating device is configured to heat the object to be heated. The single-source microwave heating device comprises a first energy divider, a microwave emitter module, a recirculating wave channel, and a recirculating wave channel. The first energy divider has one input port, one isolated port, and two output ports; opposite sides of the first energy divider are an input side and an output side, respectively. The input port and the isolated port are located on the input side. The two output ports are located on the output side. The microwave emitter module is configured to emit microwaves toward the first energy divider through the input port.The first power divider splits the microwave from the microwave emitter module between the two output ports according to a primary splitting ratio and emits the split microwave from the two output ports. Each of the two opposite ends of the phase-shifting channel is connected to one of the two output ports of the first power divider. A first phase-shifting module and a second power divider are positioned in series along the phase-shifting channel. The first phase-shifting module is configured to change the phase of a microwave passing through it. The first phase-shifting module has a first phase adjustment assembly and a first drive assembly. The phase shift provided by the first phase-shifting module varies according to the position of the first phase adjustment assembly.The first drive assembly controls the position of the first phase adjustment assembly. The second power divider has a first port, a second port, a third port, and a fourth port; two opposite sides of the second power divider are a first side and a second side, respectively. The first and second ports are located on the first side. The third and fourth ports are located on the second side. The second power divider splits a microwave entering the first port according to a first splitting ratio and emits the split microwaves from the third and fourth ports. QLbLnn / cznz / e / Yi The second power divider splits a microwave entering the second port according to a second splitting ratio and emits the split microwaves from the third and fourth ports. The second power divider splits a microwave entering the third port according to a third splitting ratio and emits the split microwaves from the first and second ports. The second power divider splits a microwave entering the fourth port according to a fourth splitting ratio and emits the split microwaves from the first and second ports. A channel between the first and fourth ports of the second power divider forms a section of the recirculating wave channel. The second and third ports of the second power divider are connected to the two opposite ends of the recirculating wave channel, respectively.A second phase-shift module and a standing-wave heating chamber are positioned in series along the circulating wave channel. The second phase-shift module is configured to change the phase of a microwave passing through it. This second phase-shift module has a second phase-adjustment assembly and a second drive assembly. The phase shift provided by the second phase-shift module varies according to the position of the second phase-adjustment assembly; the second drive assembly controls the position of the second phase-adjustment assembly. The standing-wave heating chamber is configured to accommodate the object to be heated.The microwaves emitted from the two output ports of the first power divider interfere to form a standing wave in the circulating wave channel. The positions of the standing wave crests in the circulating wave channel vary according to the position of the first phase-adjustment assembly. The standing wave in the circulating wave channel is absorbed by the object to be heated in the standing wave heating chamber. When the second phase-adjustment assembly of the second phase-shift module is moved to a phase-inversion position, the phase of one microwave entering the second power divider through the second port and exiting through the fourth port is inverted relative to the phase of another microwave entering the second power divider through the first port and exiting through the fourth port.Meanwhile, a phase of a microwave, which enters the second power divider through the third port, leaving the first port, is inverted with respect to a phase of another microwave, which enters the second power divider through the fourth port, leaving the first port. During operation, a microwave emitted by the microwave emission module is split between the two output ports of the first power divider. One microwave leaving one output port enters the standing wave heating chamber directly through one end; meanwhile, another microwave leaving the other output port passes through the first phase-shift module before entering the standing wave heating chamber through the opposite end. As a result, the two microwaves from the two output ports interfere within the standing wave heating chamber and form a standing wave. The advantage of the present invention is that the first drive assembly is capable of moving the first phase adjustment assembly back and forth, so that a phase of the microwave passing through the first phase-shifting module is repeatedly varied, thereby moving towards QLbLnn / cznz / e / Yi back and forth the positions of the crests (hot spots) of the standing wave to achieve uniform heating. Brief description of the drawings Figure 1 shows a perspective view of a first embodiment of a single-source microwave heating device according to the present invention; Figure 2 shows a partial exploded perspective view of the single-source microwave heating device in Figure 1; Figure 3 shows a cross-sectional view of the single-source microwave heating device in Figure 1; Figure 4A shows an elongated cross-sectional view of the single-source microwave heating device in Figure 1; Figure 4B shows another elongated cross-sectional view of the single-source microwave heating device in Figure 1, showing a position of a first phase-adjustment assembly of a first phase-shift module being moved; Figure 5A shows an analysis diagram showing the microwave energy volume loss density of the single-source microwave heating device in Figure 4A; Figure 5B shows an analysis diagram showing the microwave energy volume loss density of the single-source microwave heating device in Figure 4B, which shows the standing wave crest positions changing according to the position of the first phase-tuning assembly; Figure 6 shows a perspective view of a second embodiment of a single-source microwave heating device according to the present invention; Figure 7 shows a partial exploded perspective view of the single-source microwave heating device in Figure 6; Figure 8 shows a cross-sectional view of the single-source microwave heating device in Figure 6; Figure 9 shows a cross-sectional view of a third embodiment of a single-source microwave heating device according to the present invention; and Figure 10 shows a diagram with curves showing the heating efficiencies of objects that will be heated with materials of different microwave absorption versus frequency for both the first and second modes. Detailed description of preferred modalities With reference to Figures 1-3, a first embodiment of a single-source microwave heating device 1 (as shown in Figure 1) according to the present invention is configured to heat an object A. The heating device 1 comprises a first energy divider 10, a microwave emitter module 20, and a wave-changing channel 30. QLbLnn / pznz / e / Yi In the preferred embodiment, the heating device 1 further comprises an insulated port charging assembly 40. The first power divider 10 has one input port 11, one isolated port 12, and two output ports 13. Two opposite sides of the first power divider 10 are an input side 101 (as shown in Figure 3) and an output side 102 (as shown in Figure 3), respectively. The input port 11 and the isolated port 12 are located on the input side 101, while the two output ports 13 are located on the output side 102. Simply put, the two output ports 13 are located opposite the input port 11 and the isolated port 12. Ideally, the first power divider 10 is a 3-dB directional coupler, also called a four-port power divider. The S-array for an ideal 3-dB directional coupler is as follows: QLbLnn / eznz / e / Yi 0 0 ±j 0' SjdB = 1 / V2 1 0 0 ±j ±j 0 0 1 0 + / 1 o. That is, when a microwave enters the first power divider 10 through either the input port 11 or the isolated port 12 on the input side 101, the first power divider 10 splits the microwave equally between the two output ports 13 on the output side 102 and emits the split microwaves from the two output ports 13. Conversely, when a microwave is reflected and enters the first power divider 10 through either of the output ports 13, the first power divider 10 splits the microwave equally between the input port 11 and the isolated port 12. As a result, the first power divider 10 is theoretically lossless when splitting the microwave. In the preferred embodiment, the first power divider 10 is a hollow H-shaped enclosure; the input port 11, the isolated port 12, and the two output ports 13 are the four ends, respectively, of the first power divider 10. The microwave emitting module 20 emits a microwave towards the first power divider 10 by means of the input port 11. The first power divider 10 divides the microwave from the microwave emitting module 20 between the two output ports 13 according to a main division ratio and then emits the divided microwaves from the two output ports 13. In the preferred mode, the first power divider 10 is a 3-dB directional coupler as previously mentioned, and therefore the microwave entering the input port 11 is equally divided between the two output ports 13; i.e., the main division ratio is 1:1. In the preferred embodiment, the microwave emission module 20 has a microwave source 21 (as shown in Figure 1), a circulator 22 (as shown in Figure 1), a water charge 23 (as shown in Figure 1), and a first directional coupler 24 (as shown in Figure 1). The microwave source 21 is configured to generate a microwave; the circulator 22 allows the microwave to travel from the microwave source 21 to the first energy divider 10. When the microwave travels in reverse; that is, when the microwave travels from the first energy divider 10 to the microwave source 21, the circulator 22 directs the reversed microwave to the water load 23 to protect the microwave source 21. The first directional coupler 24 is configured to measure the microwave energy leaving the inlet port 11 and traveling towards the water load 23. Each of the two opposite ends of the switching wave channel 30 is connected to a respective one of the two output ports 13 of the first power divider 10. A first phase-shifting module 31 and a standing wave heating chamber 32 are located in series along the switching wave channel 30. To be precise, the wave-shifting channel 30 is formed by connecting in series a waveguide 33, a first phase-shifting module 31, and a standing-wave heating chamber 32. One end of the first phase-shifting module 31 is connected to one end of the waveguide 33, and another end of the first phase-shifting module 31 is connected to one end of the standing-wave heating chamber 32. Another end of the waveguide 33 is connected to one of the output ports 13 of the first power divider 10; another end of the standing-wave heating chamber 32 is connected to the other of the output ports 13. With reference to Figures 3, 4A, and 4B, the first phase-shifting module 31 is configured to shift one phase of a microwave passing through the first phase-shifting module 31. Preferably, the first phase-shifting module 31 has a main control body 311, two waveguides 312, a first phase-adjustment assembly 313, and a first drive assembly 314. The main control body 311 is a power divider which is substantially the same as the first power divider 10 in terms of structure. The main control body 311 has two waveguide ports 3111 and two control ports 3112. Two opposite sides of the main control body 311 are a waveguide side and a control side, respectively, wherein the two waveguide ports 3111 are located on the waveguide side and the two control ports 3112 are located on the control side. In the preferred embodiment, the first phase-shifting module 31 shifts the phase of a microwave passing through the main control body 311 by means of the two waveguide ports 3111. One of the waveguide ports 3111 is connected to the end opposite the first power divider 10 of the waveguide 33. The other of the waveguide ports 3111 is connected to the standing wave heating chamber 32, so that the microwaves in the switching wave channel 30 pass through the main control body 311 by means of the two waveguide ports 3111; i.e., a channel between two waveguide ports 3111 of the main control body 311 forms a section of the switching wave channel 30. Each of the two waveguides 312 is connected to a respective one of the two control ports 3112 of the main control body 311. In another preferred embodiment, the two waveguides 312 and the main control body 311 are integrally formed. Preferably, the first phase adjustment assembly 313 comprises two shortening pistons 3131. Each of the two shortening pistons 3131 is slidably positioned on a respective one of the two waveguides 312 and preferably, the two shortening pistons 3131 are QLbLnn / cznz / e / Yi move in a synchronized manner. The shortening pistons 3131 are configured to reflect the microwave energy into the waveguides 312. Changing the positions of the two shortening pistons 3131 increases or decreases the microwave travel length and therefore changes the phase shift provided by the first phase-shifting module 31; i.e., the phase shift provided by the first phase-shifting module 31 varies according to the position of the first phase-adjusting assembly 313. The first drive assembly 314 controls the position of the first phase adjustment assembly 313. In the preferred embodiment, the first drive assembly 314 comprises a connecting seat 3141, a drive screw 3142, a motor 3143, a mounting nut 3144, and a connecting part 3145. The connection seat 3141 is fixed relative to the two waveguides 312 of the first phase-shifting module 31. Specifically, the connection seats 3141 are fixed to the two waveguides 312. The drive screw 3142 is rotatably mounted on the connection seat 3141. The motor 3143 is mounted on the connection seat and rotates the drive screw 3142. The connection part 3145 is fixed to the mounting nut 3144, cannot rotate relative to the connection seat 3141, and is connected to the two shortening pistons 3131. In the preferred embodiment, the connecting portion 3145 has a plate and two guide shafts. The plate is fixed to the mounting nut 3144 and cannot rotate relative to the connecting seat 3141. The two guide shafts are slidably mounted through the plate, and each guide shaft is connected to one of the two shortening pistons 3131. When the motor 3143 rotates the drive screw 3142, the mounting nut 3144 is moved or driven by the drive screw 3142 along the longitudinal direction of the drive screw 3142, thereby moving the two shortening pistons 3131 by means of the plate and the two guide shafts of the connecting portion 3145. As a result, the first drive assembly 314 is able to control the positions of the two shortening pistons 3131. In the preferred embodiment, the first phase-shift module 31 is an adjustable phase control unit that is substantially assembled by a 3-dB directional coupler (the main control body 311), the two shortening pistons 3131, and the first drive assembly 314, although the first phase-shift module 31 is not limited to this. The first phase-shift module 31 may be of other types of adjustable phase control units, provided that the first phase-shift module 31 has the first drive assembly 314 and the first phase adjustment assembly 313, and the first drive assembly 314 actively controls the position of the first phase adjustment assembly 313 to change the phase shift provided by the first phase-shift module 31. The standing wave heating chamber 32 is configured to accommodate the object A to be heated. The object A to be heated is any object capable of absorbing microwave energy and being heated by it, so that the present invention can function as a heater or dryer. Preferably, an access hole (not shown in the figures) is formed through a side wall of the standing wave heating chamber 32 for placing or removing the object A to be heated. QLbLnn / cznz / e / Yi The isolated port load assembly 40 has a second directional coupler 41 (as shown in Figure 1) and a water load 42 (as shown in Figure 1) that are connected in series with the first power divider 10. The second directional coupler 41 is mounted on the isolated port 12 of the first power divider 10 and is configured to measure the microwave energy leaving the isolated port 12 and traveling to the water load 42. When the present invention is in use, the microwave emitting module 20 generates a microwave 90, which is then split by the first energy divider 10 into a forward microwave 91 and a rear microwave 92. The forward microwave 91 enters directly into the standing wave heating chamber 32 through one of the output ports 13, while the rear microwave 92 passes through the other output port 13, the waveguide 33, and the first phase-shifting module 31 before entering the standing wave heating chamber 32. The rear microwave 92 becomes the rear microwave 92' after passing through the first phase-shifting module 31, where one phase of the rear microwave 92 is changed. The forward microwave 91 and the rear microwave 92' travel toward each other and interfere in the standing wave heating chamber 32 to form a standing wave. With reference to Figures 4A, 4B, 5A and 5B, to achieve uniform heating, the first drive assembly 314 changes the positions of the two shortening pistons 3131 of the first phase adjustment assembly 313, so that one phase of the rear microwave 92' is changed, thereby changing the positions of the standing wave crests P in the standing wave heating chamber 32. Because the positions of the standing wave crests P are hot spots on the object A to be heated, the object A to be heated can be heated more uniformly by changing the positions of the standing wave crests P. In the preferred embodiment, the first drive assembly 314 of the first phase-shift module 31 drives the two shortening pistons 3131 of the first phase-adjustment assembly 313 to move continuously back and forth to achieve uniform heating. With reference to Figures 1 and 3, although the first mode is capable of achieving uniform heating, the front microwaves 91 and rear microwaves 92' are absorbed by the water charge 23 of the first energy divider 10 and the water charge 42 of the insulated port charging assembly 40 and are converted into waste heat. The microwaves are not fully absorbed by the object A to be heated during the first pass. Therefore, when the object A to be heated is a material with low microwave absorption, most of the microwaves 90 are converted into waste heat instead of heating the object A, resulting in poor heating efficiency. With reference to Figures 6-8, a second embodiment of the single-source microwave heating device 1A according to the present invention further comprises a recirculating wave channel 50A, and the switching wave channel 30A is modified so that the microwaves in the switching wave channel 30A are able to enter and circulate in the recirculating wave channel 50A. The object A to be heated is moved into the recirculating wave channel 50A, so that the microwaves that will not be QLbLnn / cznz / e / Yi absorbed by the object A to be heated in the first pass can pass, repeatedly, through and be absorbed by the object A to be heated, thereby greatly improving the heating efficiency when the object A to be heated is the low microwave absorption material. The 30A switching wave channel differs from the first mode by replacing the standing wave heating chamber 32 in the 30 switching wave channel with a second 34A power divider. The second 34A power divider is mounted between the first 31A phase-shifting module of the 30A waveform-shifting channel and the first 10A power divider. The second 34A power divider has a first port (341A), a second port (342A), a third port (343A), and a fourth port (344A). Opposite sides of the second 34A power divider are designated as the first side and the second side, respectively. The first port (341A) and the second port (342A) are located on the first side, while the third port (343A) and the fourth port (344A) are located on the second side. In short, the first port (341A) and the second port (342A) are opposite the third port (343A) and the fourth port (344A). On the first side of the second power divider 34A, the second power divider 34A splits a microwave entering the first port 341A between the third port 343A and the fourth port 344A according to a first splitting ratio and emits the split microwaves from the third port 343A and the fourth port 344A. Similarly, the second power divider 34A splits a microwave entering the second port 342A between the third port 343A and the fourth port 344A according to a second splitting ratio and emits the split microwaves from the third port 343A and the fourth port 344A. On the second side of the second power divider 34A, the second power divider 34A splits a microwave entering the third port 343A between the first port 341A and the second port 342A according to a third split ratio and emits the split microwaves from the third port 343A and the fourth port 344A, and emits the split microwaves from the first port 341A and the second port 342A. Similarly, the second power divider 34A splits a microwave entering the fourth port 344A between the first port 341A and the second port 342A according to a fourth split ratio and emits the split microwaves from the third port 343A and the fourth port 344A, and emits the split microwaves from the first port 341A and the second port 342A. In the preferred configuration, each of the second 34A power divider and the first 10A power divider is a 3-dB power divider; therefore, the microwave entering the first 341A port or the second 342A port is equally divided between the third 343A port and the fourth 344A port. Similarly, the microwave entering the third 343A port or the fourth 344A port is equally divided between the first 341A port and the second 342A port. That is, all of the first, second, third, and fourth split ratios are 1:1. QLbLnn / eznz / e / Yi A channel between the first 341A port and the fourth 344A port of the second 34A power divider forms a section of the 30A waveform shift channel. Specifically, the first 341A port is one end of the 30A waveform shift channel and is connected to one of the two 13A output ports of the first 10A power divider. The fourth 344A port is connected to the first 31A phase shift module. The second port 342A and the third port 343A of the second power divider 34A are connected to a respective two-end of the recirculating wave channel 50A. The second power divider 34A directs the microwaves in the recirculating wave channel 30A to the recirculating wave channel 50A. A second phase-shifting module 51A and a standing-wave heating chamber 52A are located in series along the circulating wave channel 50A. The second phase-shifting module 51A is configured to shift the phase of a microwave passing through the second phase-shifting module 51A. The second phase-shifting module 51A has a second phase-adjustment assembly 511A and a second drive assembly 512A. The phase shift provided by the second phase-shifting module 51A varies according to the position of the second phase-adjustment assembly 511A. The second drive assembly 512A controls the position of the second phase-adjustment assembly 511A. In the preferred embodiment, the structure of the second phase-changing module 51A is substantially the same as the structure of the first phase-changing module 31. The phase change of each of the second phase-changing modules 51A is also controlled by a drag screw which is driven by a motor; the detailed description of the second phase-changing module 51A is omitted. The standing wave heating chamber 52A is configured to accommodate object A, which will be heated. The standing wave heating chamber 52A is, although not limited to, a rectangular tube. With reference to Figure 9, the object A to be heated in a third embodiment according to the present invention is an elongated thin film used in a lamination-alamination process. For the purpose of processing the elongated thin film, a microwave heating channel 521A is formed in the standing wave heating chamber 52A. The microwave heating channel 521A moves back and forth in a zigzag pattern within the standing wave heating chamber 52A to form a sinuous channel. The object A to be heated passes through the microwave heating channel 521A by means of a slit (not shown in the figures) formed through the standing wave heating chamber 52A. With reference to Figures 3 and 8, one of the differences between the second mode and the first mode is that the microwave 90 generated by the microwave emission module 20A is directed towards the recirculating wave channel 50A, and when the second phase adjustment assembly 511A of the second phase-shifting module 51A is moved to a phase-inversion position, the recirculating wave channel 50A enters a special circulation state in which more microwaves are directed from the shifting wave channel 30A to the recirculating wave channel 50A by the second energy divider 34A, while fewer microwaves are allowed to return to the shifting wave channel 30A from the recirculating wave channel 50A, thereby causing the microwave emitted by the microwave emission module 20A to circulate and aggregate in the recirculating wave channel 50A. The detailed mechanism is explained as follows. QLbLnn / eznz / e / Yi 1 The first microwave 90 is split into the front microwave 91 and the rear microwave 92 by the first power splitter 10A. The front microwave 91 enters the second power splitter 34A via the first port 341A and is split into a front microwave 91A and a front microwave 91B. The front microwave 91A is the microwave emitted from the third port 343A, while the front microwave 91B is the microwave emitted from the fourth port 344A. The front microwave 91A is transformed into a front microwave 91A' after passing through the second phase-shifting module 51A. The front microwave 91A' is then similarly split into a front microwave 91AI and a front microwave 91A'B after returning to the second power divider 34A. The front microwave 91A'A is the microwave emitted from the third port 343A, while the front microwave 91A'B is the microwave emitted from the fourth port 344A. When the second phase adjustment assembly 511A of the second phase-shifting module 51A is moved to the phase-inversion position, one phase of the forward microwave 91A'B is inverted from one phase of the forward microwave 91B, so that the forward microwave 91A'B and the forward microwave 91B cancel each other out. Therefore, the forward microwave 91A'B is substantially prevented from returning to the shift wave channel 30A of the circulating wave channel 50A. Meanwhile, one phase of the forward microwave 91A'A is aligned with one phase of the forward microwave 91A, so that the forward microwave 91A'A and the forward microwave 91A combine to form a larger microwave. As a result, the front microwave 91 is directed entirely into the circulating wave channel 50A by the second power divider 34A and is kept in circulation and added under ideal conditions. Similarly, when the second phase adjustment assembly 511A of the second phase-shifting module 51A is moved to the phase-inversion position, the rear microwave 92 is directed into the recirculating wave channel 50A based on the same mechanism. Specifically, a phase of one microwave, entering the second power divider 34A via the third port 343A and exiting the first port 341A, is inverted relative to a phase of another microwave, entering the second power divider 34A via the fourth port 344A and exiting the first port 341A. This causes the two microwaves to cancel each other out, and therefore, the rear microwave 92 is directed entirely into the recirculating wave channel 50A, where it is kept in circulation and added under ideal conditions. The advantage of the second drive assembly 512A of the second phase-shift module 51A is that the object A being heated also changes the phases of the microwaves in the circulating wave channel 50A; that is, whenever the object A being heated is replaced with a new one, the phase inversion position of the second phase-shift assembly 511A may change and needs to be adjusted. The second drive assembly 512A actively maintains the second phase-shift assembly 511A in the correct phase inversion position so that the microwaves can aggregate in the circulating wave channel 50A. In the preferred configuration, the second 512A drive assembly is electrically connected to the first 24A directional coupler of the 20A microwave emission module and the second coupler QLbLnn / eznz / e / Yi di reacio nal 41A of the isolated port load assembly 40A so that the position of the second phase adjustment assembly 511A is controlled according to a sum of the microwave energy measured by the first directional coupler 24A and the microwave energy measured by the second directional coupler 41A. As a result, the second drive assembly 512A is able to maintain the second phase adjustment assembly 511A in the phase reversal position, automatically. To be more precise, when the second phase-adjustment assembly 511A is moved from the phase-inversion position, the forward microwave 91A'B from the fourth port 344A and the split forward microwave 91B from the forward microwave 91 are unable to cancel each other out. Therefore, some resulting microwave either travels in the reverse direction to the inlet port 11 and is then emitted to the water charge 23, or travels to the isolated port 12 and is then emitted to the water charge 42. As a result, when the second phase-adjustment assembly 511A is moved to a position where the sum of the microwave energy measured by the first directional coupler 24A and the second directional coupler 41A is at a minimum, the second phase-adjustment assembly 511A is in the optimal phase-inversion position. With reference to Figure 10, the curves show the heating efficiency of objects A, which will be heated with materials of different microwave absorption, versus frequency. Heating efficiency is defined as the proportion of heat generated in the object by the microwaves. Curve 93 shows the relationship between the low microwave absorption material and frequency in the first mode. Curve 93' shows the relationship between the low microwave absorption material and frequency in the second mode. When the second phase-adjustment assembly 511A in the second mode is moved to the phase-inversion position (corresponding to a microwave frequency of approximately 915 MHz), the heating efficiency is improved from 14% in the first mode to 57% in the second mode. As a result, the second mode has an unexpected advantage over the first mode. Similarly, curve 94 shows the relationship between the medium microwave absorption material and the frequency in the first mode. Curve 94' shows the relationship between the medium microwave absorption material and the frequency in the second mode. The heating efficiency is improved from 25% in the first mode to 81% in the second mode. Curve 95 shows the relationship between the high microwave absorption material and the frequency in the first mode. Curve 95' shows the relationship between the high microwave absorption material and the frequency in the second mode. The heating efficiency is improved from 56% in the first mode to 97% in the second mode. In summary, by using the first power divider 10 to split the microwave emitted by the microwave emission module 20 into two microwaves traveling towards each other to form a standing wave, and by using the first phase-shifting module 31 to shift the phase of one of the two microwaves, the positions of the crests (hot spots) of the standing wave can be moved back and forth in the shifting wave channel 30 to achieve uniform heating.

Claims

1. A single-source microwave heating device configured for heating an object to be heated; the single-source microwave heating device comprising: a first energy divider having an inlet port, an isolated port, and two outlet ports; two opposite sides of the first energy divider are, respectively, on an inlet side and an outlet side; the inlet port and the isolated port are located on the inlet side; and the two outlet ports are located on the outlet side; a microwave emitting module configured to emit a microwave towards the first energy divider by means of the inlet port; the first energy divider divides the microwave from the microwave emitting module between the two outlet ports according to a major splitting ratio and emits the split microwaves from the two outlet ports; and a wave-switching channel;Each of the two opposite ends of the waveform switching channel is connected to one of the two output ports of the first power divider; a first phase-shifting module and a standing-wave heating chamber are positioned in series along the waveform switching channel; wherein the first phase-shifting module is configured to shift the phase of a microwave passing through the first phase-shifting module; the first phase-shifting module has a first phase-adjustment assembly and a first drive assembly; the phase shift provided by the first phase-shifting module varies according to the position of the first phase-adjustment assembly; the first drive assembly controls the position of the first phase-adjustment assembly; and the standing-wave heating chamber is configured to accommodate the object to be heated;wherein the microwaves emitted from the two output ports of the first power divider interfere to form a standing wave in the switching wave channel; the positions of the standing wave crests in the switching wave channel vary according to a position of the first phase-adjustment assembly; wherein the standing wave in the switching wave channel is absorbed by the object to be heated in the standing wave heating chamber to heat the object.

2. The single-source microwave heating device according to claim 1, wherein the first drive assembly of the first phase-shift module drives the first phase-adjustment assembly to move back and forth.

3. The single-source microwave heating device according to claim 1, QLbLnn / cznz / e / Yi wherein the first phase-shifting module comprises: a main control body that is a power divider; the main control body having two waveguide ports and two control ports; two opposite sides of the main control body are, respectively, on a waveguide side and a control side; the two waveguide ports are located on the waveguide side; and the two control ports are located on the control side; and two waveguides; one end of each of the waveguides is connected to one of the two control ports of the main control body; the first phase-adjustment assembly comprises: two shortening pistons slidably located on the two waveguides, respectively;and the first drive assembly of the first phase-shift module is connected to the two shortening pistons and controls the positions of the two shortening pistons in the two waveguides.

4. The single-source microwave heating device according to claim 3, wherein the first drive assembly of the first phase-shift module comprises: a connection seat fixed relative to the two waveguides of the first phase-shift module; a drive screw rotatably mounted on the connection seat; a motor mounted on the connection seat and rotating the drive screw; a mounting nut threaded onto the drive screw; and a connecting portion fixed to the mounting nut and non-rotating relative to the connection seat; the connecting portion being connected to the two shortening pistons.

5. The single-source microwave heating device according to claim 1, wherein the first power divider is a 3-dB directional coupler.

6. A single-source microwave heating device configured for heating an object to be heated; the single-source microwave heating device comprising: a first energy divider having an inlet port, an isolated port, and two outlet ports; two opposite sides of the first energy divider are, respectively, on an inlet side and an outlet side; the inlet port and the isolated port are located on the inlet side; and the two outlet ports are located on the outlet side; a microwave emitting module configured to emit a microwave towards the first energy divider by means of the inlet port; the first energy divider divides the microwave from the microwave emitting module between the two outlet ports according to a major splitting ratio and emits the divided microwave from the two outlet ports; and a wave-switching channel;Each of the two opposite ends of the waveform switching channel is connected to a respective one of the two output ports of the first power divider; a first phase-shifting module and a second power divider are positioned in series along the waveform switching channel; wherein the first phase-shifting module is configured to shift one phase of a microwave passing through the first phase-shifting module; the first phase-shifting module has a first phase-adjustment assembly and a first drive assembly; the phase shift provided by the first phase-shifting module varies according to the position of the first phase-adjustment assembly; the first drive assembly controls the position of the first phase-adjustment assembly; the second power divider has a first port, a second port, a third port, and a fourth port;The two opposite sides of the second power divider are, respectively, on a first side and a second side; the first port and the second port are located on the first side; the third port and the fourth port are located on the second side; the second power divider divides a microwave entering the first port according to a first division ratio and emits the divided microwaves from the third port and the fourth port; the second power divider divides a microwave entering the second port according to a second division ratio and emits the divided microwaves from the third port and the fourth port; the second power divider divides a microwave entering the third port according to a third division ratio and emits the divided microwaves from the first port and the second port;the second power divider that divides a microwave entering the fourth port according to a fourth division ratio and emits the divided microwaves from the first port and the second port; a channel between the first port and the fourth port of the second power divider that forms a section of the recirculating wave channel; a recirculating wave channel, wherein the second port and the third port of the second power divider are connected to the two opposite ends of the recirculating wave channel, respectively; a second phase-shifting module and a standing-wave heating chamber are situated in series and along the recirculating wave channel; wherein the second phase-shifting module is configured to shift the phase of a microwave passing through the second phase-shifting module; the second phase-shifting module has a second phase-adjustment assembly and a second drive assembly;A phase shift provided by the second phase-shift module varies according to the position of the second phase-adjustment assembly; the second drive assembly controls the position of the second phase-adjustment assembly; and the standing-wave heating chamber is configured to accommodate the object to be heated; wherein the microwaves emitted from the two output ports of the first power divider interfere to form a standing wave in the circulating wave channel; the positions of the standing wave crests in the circulating wave channel vary according to the position of the first phase-adjustment assembly; wherein the standing wave in the circulating wave channel is absorbed by the object to be heated in the standing-wave heating chamber to heat the object;wherein when the second phase adjustment assembly of the second phase-shift module is moved to a phase-inversion position, a phase of a microwave, entering the second power divider through the second port, leaving the fourth port, is inverted with respect to a phase of another microwave, entering the second power divider through the first port, leaving the fourth port; meanwhile, a phase of a microwave, entering the second power divider through the third port, leaving the first port, is inverted with respect to a phase of another microwave, entering the second power divider through the fourth port, leaving the first port.

7. The single-source microwave heating device according to claim 6, further comprising: a first directional coupler mounted between the microwave emitter module and the inlet port of the first power divider; the first directional coupler being configured to measure the microwave energy leaving the inlet port; and a second directional coupler mounted on the insulated port of the first power divider and configured to measure the microwave energy leaving the insulated port; wherein the second drive assembly of the second phase-shift module is electrically connected to the first directional coupler and the second directional coupler such that the position of the second phase-shift assembly is controlled according to a sum of the microwave energy measured by the first directional coupler and the microwave energy measured by the second directional coupler.

8. The single-source microwave heating device according to claim 6, wherein the second power divider is a 3-dB directional coupler.

9. The single-source microwave heating device according to claim 6, QLbLnn / cznz / e / Yi wherein each of the first power divider and the second power divider is a 3-dB directional coupler.

10. The single-source microwave heating device according to claim 6, wherein a sinuous microwave heating channel is formed in the standing wave heating chamber.

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