The present application claims priority from Japanese patent application JP 2011-153876 filed on Jul. 12, 2011, the content of which is hereby incorporated by reference into this application.
The present invention relates to an electromagnetic wave propagation apparatus and an electromagnetic wave interface. More particularly, the invention relates to an electromagnetic wave propagation apparatus using a planar propagation medium to two-dimensionally propagate an electromagnetic wave and an electromagnetic wave interface used for this apparatus.
In recent years, there is an increasing demand for networking electronic units in many fields including consumers and society's infrastructures. The number of cables connecting between units tends to increase. On the other hand, the wireless trend evolves in data transmission such as wireless LAN (Local Area Network). There is also an increasing demand for wireless power supply. However, the wireless power supply technology is commercialized for only IH cooking heaters, shavers, and cordless telephones that transmit power at a very short distance almost in a contacted state. Degraded transmission efficiency due to radio wave diffusion seriously bottlenecks the three-dimensional power transmission in terms of several meters or several watts or more. The use of the wireless power supply technology remains stagnant. Incorrect positioning greatly degrades characteristics of an electronic unit for which the wireless power supply is commercialized. The electronic unit needs to be placed at a specified position and is prone to a low degree of freedom for placement.
For example, Japanese Unexamined Patent Application Publication No. 2010-093446 discloses the planar propagation medium as a technology to solve these problems. The technology can transmit an electromagnetic wave between two planar conductors that sandwich a planar dielectric. One of the planar conductors is formed in a meshed pattern. The electromagnetic wave interface is provided via a thin-film dielectric. An evanescent wave leaking near the meshed conductor enables output and input of an electromagnetic wave. The same publication discloses the surface wave transmission system that propagates an electromagnetic wave referred to as a surface wave trapped in the planar propagation medium. This system two-dimensionally transmits power along the planar propagation medium and enables higher efficiency than the three-dimensional transmission. Just placing an object to be powered on the planar propagation medium enables power transmission. The system ensures a high degree of freedom for placement and is expected to be applicable to continuous power supply to mobile objects.
Japanese Unexamined Patent Application Publication No. 2009-188737 discloses the technology of miniaturizing an ordinary antenna used in the free space. Dipole antennas are modified to provide two L-shaped dipole antennas. These antennas are symmetrically placed at opposite corners on a conductive plate. A power supply point is provided at the end of a signal conductor for each antenna.
Japanese Unexamined Patent Application Publication No. 2010-093446 uses electromagnetic wave coupling. Therefore, the size of an electromagnetic wave interface depends on wavelengths in the planar propagation medium and tends to increase. To solve this problem, the same publication discloses the following technology. The technology couples a spiral conductor for the electromagnetic wave interface and a meshed conductor for the planar propagation medium using mutual inductance M between them. The technology shortens the distance between both conductors and miniaturizes the electromagnetic wave interface without decreasing the mutual inductance. However, this electromagnetic wave interface miniaturization technology varies the mutual inductance due to relative positional relationship between the spiral conductor and the meshed conductor. The power receiving amount is unstable. The technology disclosed in Japanese Unexamined Patent Application Publication No. 2010-093446 is hardly applicable to continuous power supply to mobile objects where the positional dependence of power supply characteristics is important. For the purpose of positional dependence improvement or miniaturization, shortening distance Im between lines on the spiral conductor causes another problem such as a decreased self-resonant frequency due to increased parasitic capacitance.
The miniaturization technology described in Japanese Unexamined Patent Application Publication No. 2009-188737 provides the planar antenna using two L-shaped dipole antennas placed oppositely. The power is supplied from the center of the L-shaped dipole antennas. Theoretically, the miniaturization is just limited to approximately a quarter wavelength. The linear antenna narrows an operating frequency band. The antenna cannot be easily miniaturized in combination with a power receiving circuit including a rectifier and a regulator.
The present invention has been made in consideration of the foregoing. It is therefore an object of the invention to provide a small-sized electromagnetic wave interface and an electromagnetic wave propagation apparatus using the same so that the electromagnetic wave interface is used for a surface wave transmission system, features a small positional dependence of power supply characteristics, and is proper to continuously supply power to a mobile object.
A representative aspect of the present invention is described as follows. An electromagnetic wave propagation apparatus according to the invention propagates an electromagnetic wave as electric power or information between a base station and a terminal. The electromagnetic wave propagation apparatus includes: a planar propagation medium including a planar conductor, a first planar dielectric, a planar mesh conductor, and a second planar dielectric that are overlaid on each other in order; at least one electromagnetic wave input port that functions as a first interface to connect the base station with the planar propagation medium; and an electromagnetic wave interface that is provided on the second planar dielectric and functions as a second interface to connect the terminal with the planar propagation medium. The electromagnetic wave interface includes a planar dielectric board and a plurality of planar conductor patterns parallel provided so as to sandwich part of the dielectric board. The conductor patterns include a first conductor pattern that is provided toward the planar propagation medium. The first conductor pattern includes at least one corner. At least one connection means is provided between the first conductor pattern and the terminal. At least one short-circuit means is provided to electrically short-circuit the conductor patterns at the corner of the first conductor pattern.
The aspect of the invention can decrease the positional dependence of power supply characteristics.
According to a representative embodiment of the invention, an electromagnetic wave propagation apparatus includes: a planar propagation medium including a planar conductor, a first planar dielectric, a planar mesh conductor, and a second planar dielectric that are overlaid on each other in order; at least one electromagnetic wave input port provided for the planar propagation medium; a power supply station (base station) that supplies the planar propagation medium with an electromagnetic wave as electric power or information through the electromagnetic wave input port; and at least one power receiving apparatus that is provided for a second planar dielectric of the planar propagation medium and includes an electromagnetic wave interface and a power receiving circuit. A dielectric board is provided with multiple conductor patterns as the electromagnetic wave interface. At least one connection means is provided between the conductor pattern and the power receiving circuit. At least one short-circuit means between the conductor patterns is provided at a corner of the conductor pattern. The electromagnetic wave propagation apparatus can use the small-sized electromagnetic wave interface that is used for a surface wave transmission system, features a small positional dependence of power supply characteristics, and is proper to continuously supply power to a mobile object. In particular, a dielectric area occupancy can adjust the power receiving amount. The dielectric area occupancy signifies the occupancy of an area containing the exposed dielectric and no planar mesh conductor provided in the area of the planar propagation medium covered with the electromagnetic wave interface. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor is shaped so as to decrease a variation in the dielectric area occupancy. In addition, the electromagnetic wave propagation apparatus is capable of wide-band operation.
According to another feature of the electromagnetic wave propagation apparatus, the conductor patterns include: a first conductor pattern provided toward the planar propagation medium; and a second conductor pattern provided nearer to the power receiving apparatus than the first conductor pattern. At least one through via is provided as a connection means between the first conductor pattern and the power receiving circuit. At least one short via is provided as a short-circuit means between the first conductor pattern and the second conductor pattern at an end of the first conductor pattern. According to the electromagnetic wave propagation apparatus, the electromagnetic wave interface can be manufactured through a general-purpose substrate forming process using a glass-epoxy printed substrate. As a result, the wireless power supply system can be provided inexpensively.
According to still another feature of the electromagnetic wave propagation apparatus, the outline of the second conductor pattern covers the outline of the first conductor pattern when the electromagnetic wave propagation apparatus is seen through in a direction perpendicular to the dielectric. The electromagnetic wave propagation apparatus can provide the electromagnetic wave interface with a large ground area to ensure stable operation.
According to yet another feature of the electromagnetic wave propagation apparatus, the short via is provided at the corner of the first conductor pattern. The electromagnetic wave propagation apparatus short-circuits one end face of the first conductor pattern and decreases a resonant frequency for the electromagnetic wave interface. As a result, the electromagnetic wave interface can be miniaturized.
According to still yet another feature of the electromagnetic wave propagation apparatus, the through via is provided along the diagonal including the corner of the first square conductor pattern provided with the short via. According to the electromagnetic wave propagation apparatus, the through via can elongate the current path on the first conductor pattern and decreases a resonant frequency for the electromagnetic wave interface. As a result, the electromagnetic wave interface can be miniaturized.
According to yet still feature of the electromagnetic wave propagation apparatus, multiple through vias provided at the different corners outside a diagonal of the first conductor pattern each produce reception power and the power receiving circuit synthesizes the reception powers supplied with a given phase difference. The electromagnetic wave propagation apparatus can apply a given phase difference to reception powers acquired at multiple through vias and synthesize the reception powers to decrease directionality of the electromagnetic wave interface. Alternatively, the electromagnetic wave propagation apparatus can apply strong directionality to the arrival direction of the electromagnetic wave and receive more power.
According to still yet feature of the electromagnetic wave propagation apparatus, the power receiving circuit is provided on the dielectric board. According to the electromagnetic wave propagation apparatus, the power receiving apparatus includes the electromagnetic wave interface and the power receiving circuit and can be integrally mounted on a general-purpose printed substrate. Therefore, miniaturization and cost reduction effects can be promoted.
According to yet still feature of the electromagnetic wave propagation apparatus, an end face or an inside of the dielectric board is provided with a shield conductor or a wave absorber that shields an electromagnetic wave. The electromagnetic wave propagation apparatus can prevent an electromagnetic wave from leaking from the edge of the second conductor pattern and contribute to highly effective power transmission.
Embodiments of the present invention will be described in further detail with reference to the accompanying drawings.
The following describes an electromagnetic wave propagation apparatus according to a first embodiment of the invention with reference to
The electromagnetic wave propagation apparatus 100 propagates an electromagnetic wave as electric power or information between a base station 200 and a terminal 300. According to an example configuration described below, the base station 200 includes a power supply station 7. The terminal 300 includes a unit 22 to be powered. Power is unidirectionally supplied from the power supply station 7 to the unit 22.
The electromagnetic wave propagation apparatus 100 supplies power or information to the unit 22 to be powered from the power supply station 7. The electromagnetic wave propagation apparatus 100 includes a planar propagation medium 5, a power receiving apparatus 23, and an electromagnetic wave input port 6.
The planar propagation medium 5 provides a propagation path for an electromagnetic wave as power or information. As shown in
The electromagnetic wave input port 6 in
A terminal 300 of the electromagnetic wave propagation apparatus 100 is placed on the planar propagation medium 5. The power receiving apparatus 23 of the terminal 300 includes an electromagnetic wave interface 8 (second interface) and a power receiving circuit 16 provided for the dielectric substrate 11. The electromagnetic wave interface 8 includes a first conductor pattern 9, a second conductor pattern 10, a short via 12, and a through via 13. The short via 12 and the through via 13 electrically short-circuit the conductor patterns. To form the via, a drill or laser is used to bore a hole through the dielectric substrate 11. The hole is metal-plated inside.
The electromagnetic wave interface 8 enables miniaturization by decreasing a resonant frequency through the use of capacitance between the first conductor pattern 9 and the second conductor pattern 10 that excite two coupling modes. The dielectric substrate 11 includes three parallel layers of conductors, that is, the first conductor pattern 9, the second conductor pattern 10, and a circuit mounting conductor 15. The first conductor pattern 9 contacts with the planar propagation medium 5. The second conductor pattern 10 is used as an intermediate conductor layer. The circuit mounting conductor 15 is provided as the topmost layer opposite the planar propagation medium 5. The electromagnetic wave interface 8 receives power from the planar propagation medium 5. The power is fed to the power receiving circuit 16 on the circuit mounting conductor 15 through the through via 13. The power receiving circuit 16 rectifies the power. The power is transformed into a direct current of a specified voltage. The direct current is then supplied to the unit 22.
As shown in
Shapes of the first conductor pattern and the second conductor pattern are not limited to squares. The present invention is applicable to rectangles and any polygons. The same applies to the other embodiments. Any planar shape preferably contains at least one corner to provide the first conductor pattern 9 with the short via 12. As shown in
If the first conductor pattern and the second conductor pattern are rectangular, selecting their sizes enables operation as a circularly polarized wave. As a result, a less directional electromagnetic wave interface can be provided.
The following describes positional dependence of the power receiving amount on the electromagnetic wave interface.
Equation (1) expresses a variation range containing the maximum variation amount in dielectric area occupancy D and second conductor pattern length gdl' under this condition.
In this equation, n denotes the natural number. As a calculation example, let us assign the parameter conditions for the simulation in
The embodiment has described the example of the first conductor pattern 9 and the second conductor pattern 10 both shaped into squares. As described above, the present invention is also applicable to rectangles and any polygons. If the patterns are rectangular, selecting their sizes enables operation as a circularly polarized wave. As a result, a less directional electromagnetic wave interface can be provided.
The power supply station 7 preferably supplies power at a high efficiency of electric power transmission. The efficiency signifies a ratio between consumed power and transmission power for the power supply station 7. Reception power for the power receiving apparatus 23 varies with its positions on the planar propagation medium 5. It is preferable to keep the reception power constant by adjusting and compensating the transmission power for the power supply station 7. Alternatively, a large amount of power is preferably transmitted when the efficiency of electric power transmission is high. The transmission power is preferably varied in accordance with the consumed power or the operation state of the unit 22 connected to the power receiving apparatus 23. That is, the power supply station 7 preferably provides a high efficiency of electric power transmission in terms of a wide range of transmission power such as 10 dB.
For this purpose, each power supply voltage converter 53 adjusts the power supply voltage for each power amplifier 56 and each variable gain amplifier 55 adjusts the input power for each power amplifier 56 in accordance with the targeted transmission power based on states of the unit 22. That is, the power supply voltage and the input power for the power amplifier 56 are increased as the targeted transmission power increases. As a result, the power amplifier 56 can be used in a saturated state over a wide range of transmission power. The efficiency of electric power transmission can be kept high.
The power detector 58 detects the power input to or output from each power amplifier 56 to determine whether the power amplifier 56 outputs the targeted transmission power in a saturated state. The power detector 58 detects the power output from each power amplifier 56 to determine whether the targeted transmission power is output. The power detector 58 detects the power input to each power amplifier 56 to detect the power gain for each power amplifier 56 and determine whether each power amplifier 56 operates in a saturated state.
The power amplifier 56 preferably uses a constant power gain regardless of the transmission power if the consumed power for the power amplifier 56 accounts for a large percentage of the entire consumed power for the power supply station 7. By contrast, the power gain for the power amplifier 56 is preferably increased as the transmission power decreases if the consumed power for the components other than the power amplifier 56 accounts for a large percentage thereof.
The controller 57 controls the phase regulation amount for each phase shifter 54 so that electromagnetic waves output from the electromagnetic wave input ports 6 are mutually increased at the position for the power receiving apparatus 23 on the planar propagation medium 5. As a result, the reception power for the power receiving apparatus 23 is preferably increased. Alternatively, the controller 57 preferably controls each phase regulation amount so that electromagnetic waves output from the electromagnetic wave input ports 6 are mutually canceled at a position other than the power receiving apparatus 23 on the planar propagation medium 5 or at a position where power transmission needs to be avoided.
The power receiving circuit 16 will be described below.
The voltage/current detector 61 uses a tiny resistor to convert a current flowing from the series-parallel rectifier 60 to the regulator 62 into a voltage and detects it. The voltage/current detector 61 may use an analog-digital converter to convert the detected voltage as well as the voltage input to the regulator 62 into digital values.
The reception power supplied from the electromagnetic wave interface 8 varies with the transmission power from the power supply station 7 or the position of the power receiving apparatus 23 on the planar propagation medium 5. The necessary voltage or power varies with the consumed power or the operation state of the unit 22. In consideration of these, the series-parallel rectifier 60 preferably maintains a high efficiency of electric power reception over a wide range of reception power such as approximately 10 dB.
For this purpose, the controller 63 controls the number of series or parallel rectifiers 64 in the series-parallel rectifier 60.
In
This configuration can change the number of series or parallel rectifiers 64 while maintaining the input impedance of the series-parallel rectifier 60 to be constant. A wide range of reception power can be efficiently received.
Similarly to
This configuration can change the number of series or parallel rectifiers 64 while maintaining the input impedance for the series-parallel rectifier 60 to be constant without adding an element in series to the reception power line. A wide range of reception power can be efficiently received.
The examples in
The switches 65, 66, 67, and 68 just need to provide an electric function equivalent to a switch at a given frequency to be used. For example, a variable capacitor maybe used. The capacitance value can be increased when the switches 65, 66, 67, and 68 are short-circuited. The capacitance value can be decreased when the same switches are opened. Similarly, it may be preferable to use a variable resistor or other elements capable of varying electric characteristics.
According to the embodiment, the short via 12 short-circuits the first conductor pattern 9 and the second conductor pattern 10. The short via 12 is not limited to a circular shape and may be replaced by a different means only if it can short-circuit both patterns. The dielectric substrate 11 containing three layers of conductors may use different materials for substrates bonded to each other. The electromagnetic wave interface 8 and the power receiving circuit 16 may be physically separated.
The embodiment has described the electromagnetic wave interface 8 used for power reception. The electromagnetic wave interface 8 may be used as the electromagnetic wave input port 6 for power transmission in order to promote miniaturization.
The first embodiment has described the electromagnetic wave propagation apparatus 100 as a power supply apparatus. The power supply station 7 and the power receiving circuit 16 may be replaced by a communication base station and a receiver, respectively. As a result, the electromagnetic wave propagation apparatus 100 can transmit an electromagnetic wave as a communication signal or a control signal between units, not as the electric power. Obviously, configuration combinations enable both signals to be transmitted simultaneously or under time sharing control.
The base station 200 and the terminal 300 according to the invention may each include a function of transmitting and receiving electromagnetic waves via the electromagnetic wave propagation apparatus 100 and bidirectionally exchange information. In this case, each terminal 300 includes a power supply station as well as the power receiving circuit. The base station 200 includes a power receiving circuit as well as the power supply station. For example, there may be a system that transmits power or control signals to the terminals 300 from the base station 200 and transmits response information or measurement data to the base station 200 from the terminals 300.
For example, the unit 22 of the terminal 300 may be equivalent to a mobile object such as a robot that is used for medical care, nursing care, or security and moves on the planar propagation medium 5. The electromagnetic wave propagation apparatus 100 enables wireless, contactless, and highly reliable continuous power supply and communication from the base station to the mobile object and allows the mobile object to perform specified tasks. The mobile object can operate for a long time without the need to mount a heavy battery.
As described above, the electromagnetic wave propagation apparatus 100 according to the first embodiment decreases a resonant frequency using the capacitance between the first conductor pattern 9 and the second conductor pattern 10 for exciting two coupling modes and the capacitance between the planar mesh conductor 4 and both conductor patterns. The short via 12 short-circuits both conductor patterns. The through via 13 is provided as a power supply point on the diagonal of the first conductor pattern 9. As a result, the electromagnetic wave interface 8 can be miniaturized and is capable of wide-band operation.
The electromagnetic wave propagation apparatus according to the embodiment provides the short via at the corner of the first conductor pattern. The short via short-circuits one end face of the first conductor pattern and decreases a resonant frequency for the electromagnetic wave interface. As a result, the electromagnetic wave interface can be miniaturized. The electromagnetic wave propagation apparatus according to the embodiment provides the through via along the diagonal including the corner of the first square conductor pattern provided with the short via. The through via can elongate the current path on the first conductor pattern and decreases a resonant frequency for the electromagnetic wave interface. As a result, the electromagnetic wave interface can be miniaturized.
According to the first embodiment, the power receiving apparatus 23 includes the electromagnetic wave interface 8 and the power receiving circuit 16 and can be integrally mounted on a general-purpose printed substrate. Therefore, miniaturization and cost reduction effects can be promoted. The electromagnetic wave propagation apparatus according to the embodiment provides the dielectric board with conductor patterns, that is, the first conductor pattern and the second conductor pattern that are both planar. At least one through via is provided as a means to connect the first conductor pattern and the power receiving circuit. At least one short via is provided as a means to short-circuit the first conductor pattern and the power receiving circuit at a corner of the first conductor pattern. The electromagnetic wave interface contains a layer of planar members. For example, the electromagnetic wave interface can be manufactured through a general-purpose substrate forming process using a glass-epoxy printed substrate. As a result, the wireless power supply system can be provided inexpensively.
The outline of the second conductor pattern covers the outline of the first conductor pattern when the electromagnetic wave propagation apparatus according to the embodiment is seen through in a direction perpendicular to the dielectric. The electromagnetic wave interface can be provided with a large ground area to ensure stable operation.
The electromagnetic wave interface 8 used for the electromagnetic wave propagation apparatus 100 according to the first embodiment can adjust the power receiving amount in accordance with the dielectric area occupancy. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor 4 is shaped so as to decrease a variation in the dielectric area occupancy.
The electromagnetic wave propagation apparatus according to the embodiment can miniaturize the electromagnetic wave interface so as to be capable of wide-band operation. The power receiving amount can be adjusted in accordance with the dielectric area occupancy. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor 4 is shaped so as to decrease a variation in the dielectric area occupancy.
The second embodiment of the invention will be described below.
The electromagnetic wave propagation apparatus 100 propagates an electromagnetic wave as electric power or information between the base station 200 and the terminal 300. Similarly to the first embodiment, the following describes an example configuration in which power is unidirectionally supplied from the power supply station 7 to the unit 22.
The electromagnetic wave propagation apparatus 100 allows the power supply station 7 to supply power to the unit 22 to be fed. The electromagnetic wave propagation apparatus 100 includes the planar propagation medium 5, the power receiving apparatus 23, and the electromagnetic wave input port 6. The power receiving apparatus 23 includes the electromagnetic wave interface 8 and the power receiving circuit 16 both provided for the dielectric substrate 11. The electromagnetic wave interface 8 includes the first square and planar conductor pattern 9, the second square and planar conductor pattern 10, the short via 12, the through via 13, the shield via group 19, and the shield conductor 20. To form the short via 12, the through via 13, and the shield via group 19, a drill or laser is used to bore a hole through the dielectric substrate 11. The hole is metal-plated inside. The power supply station 7 and the power receiving circuit 16 have the same configurations and functions as the first embodiment.
The electromagnetic wave interface 8 enables miniaturization by decreasing a resonant frequency through the use of capacitance between the first conductor pattern 9 and the second conductor pattern 10 that excite two coupling modes. The dielectric substrate 11 includes three layers of conductors. The first conductor pattern 9 forms a conductor layer in contact with the planar propagation medium 5. The second conductor pattern 10 forms an intermediate conductor layer. The circuit mounting conductor 15 forms a layer opposite the planar propagation medium 5. The electromagnetic wave interface 8 receives power from the planar propagation medium 5. The power is fed to the power receiving circuit 16 on the circuit mounting conductor 15 through the through via 13. The power receiving circuit 16 rectifies the power. The power is transformed into a specified voltage. The power is then supplied to the unit 22. The shield via group 19 and the shield conductor 20 are connected to the second conductor pattern 10 and prevent an electromagnetic wave from leaking from the edge of the second conductor pattern 10. The shield via group 19 and the shield conductor 20 contribute to highly effective power transmission.
As shown in
The embodiment has described the configuration using the shield via group 19 and the shield conductor 20 as a means to prevent an electromagnetic wave from leaking from the electromagnetic wave interface. As an alternative, an end face of the dielectric substrate 11 maybe provided with a metal foil or a wave absorber operating at a usable frequency band.
The embodiment has described the electromagnetic wave interface 8 used for power reception. The electromagnetic wave interface 8 may be used as the electromagnetic wave input port 6 for power transmission in order to promote miniaturization.
As described above, the electromagnetic wave propagation apparatus 100 according to the second embodiment decreases a resonant frequency using the capacitance between the first conductor pattern 9 and the second conductor pattern 10 for exciting two coupling modes and the capacitance between the planar mesh conductor 4 and both conductor patterns. The short via 12 short-circuits both conductor patterns. The through via 13 is provided as a power supply point on the diagonal of the first conductor pattern 9. The shield via group 19 and the shield conductor 20 are connected to the second conductor pattern 10. As a result, the electromagnetic wave interface 8 can be miniaturized and is capable of wide-band operation.
The electromagnetic wave interface 8 used for the electromagnetic wave propagation apparatus 100 according to the second embodiment is provided with the shield via group 19 and the shield conductor 20. The shield via group 19 and the shield conductor 20 can prevent an electromagnetic wave from leaking from the edge of the second conductor pattern 10 and contribute to highly effective power transmission.
The electromagnetic wave interface 8 used for the electromagnetic wave propagation apparatus 100 according to the second embodiment can adjust the power receiving amount in accordance with the dielectric area occupancy. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor 4 is shaped so as to decrease a variation in the dielectric area occupancy.
According to the second embodiment, the power receiving apparatus 23 includes the electromagnetic wave interface 8 and the power receiving circuit 16 and can be integrally mounted on a general-purpose printed substrate. Therefore, miniaturization and cost reduction effects can be promoted.
The second embodiment has described the electromagnetic wave propagation apparatus 100 as a power supply apparatus. The power supply station 7 and the power receiving circuit 16 may be replaced by a communication base station and a receiver, respectively. As a result, the electromagnetic wave propagation apparatus 100 can transmit an electromagnetic wave as a communication signal or a control signal between units, not as the electric power. Obviously, configuration combinations enable both signals to be transmitted simultaneously or under time sharing control.
The base station 200 and the terminal 300 may each include a function of transmitting and receiving electromagnetic waves and bidirectionally exchange information. In this case, each terminal 300 includes a power supply station as well as the power receiving circuit. The base station 200 includes a power receiving circuit as well as the power supply station. For example, there may be a system that transmits power or control signals to the terminals 300 from the base station 200 and transmits response information or measurement data to the base station 200 from the terminals 300.
The third embodiment of the invention will be described below.
The electromagnetic wave interface 8 enables miniaturization by decreasing a resonant frequency through the use of capacitance between the first conductor pattern 9 and the second conductor pattern 10 that excite two coupling modes. The dielectric substrate 11 includes three layers of conductors. The first conductor pattern 9 forms a conductor layer in contact with the planar propagation medium 5. The second conductor pattern 10 forms an intermediate conductor layer. The circuit mounting conductor 15 forms a layer opposite the planar propagation medium 5. The electromagnetic wave interface 8 receives power from the planar propagation medium 5. The power is fed to the power receiving circuit 16 on the circuit mounting conductor 15 through the through vias 13a and 13b. The power receiving circuit 16 rectifies the power. The power is transformed into a specified voltage. The power is then supplied to the unit 22.
As shown in
The electromagnetic wave interface is preferably non-directional. Multiple reflection occurs inside the planar propagation medium 5 if it has a short-circuited or opened reflection end face. The arrival direction of an electromagnetic wave may vary with positions. This problem is alleviated if a wave absorber operating at the usable frequency is provided for the end face of the planar propagation medium 5. However, components absorbed in the wave absorber result in a loss. It is important to evenly receive electromagnetic waves in all arrival directions inside the planar propagation medium 5 from the viewpoint of accessibility to the electromagnetic wave interface 8. The through vias 13a and 13b produce the power that contains electromagnetic field components excited by mutually orthogonal resonant modes 26a and 26b. The resonant modes 26a and 26b cause a 90-degree phase difference. That is, the resonant modes 26a and 26b operate equivalently to an ordinary circular polarized receiving antenna and evenly receive electromagnetic waves in all arrival directions. The power produced from the through vias 13a and 13b is given a 90-degree phase difference and is synthesized at a stage previous to the rectifier in the power receiving circuit 16. As a result, a less directional power receiving apparatus 23 can be provided. The power can be explicitly given directionality if the phase difference is adjusted to synthesize the power. More power can be received if the arrival direction of an electromagnetic wave is known.
The embodiment has described the electromagnetic wave interface 8 using two sets of through vias and short vias. More variable or smaller directionality is available if three or more through vias are used depending on planar shapes of the first conductor pattern 9. If the first conductor pattern 9 and the second conductor pattern 10 are both hexagonal, for example, three sets of through vias and short vias may be provided at three corners outside the diagonal of the first conductor pattern 9. If the first conductor pattern 9 and the second conductor pattern 10 are both octagonal, four sets of through vias and short vias may be provided at four corners outside the diagonal of the first conductor pattern 9. Accordingly, two sets of through vias and short vias can be located at any corners depending on planar shapes of the first conductor pattern 9.
The embodiment has described the electromagnetic wave interface 8 used for power reception. The electromagnetic wave interface 8 may be used as the electromagnetic wave input port 6 for power transmission in order to promote miniaturization.
As described above, the electromagnetic wave propagation apparatus 100 according to the third embodiment decreases a resonant frequency using the capacitance between the first conductor pattern 9 and the second conductor pattern 10 and the capacitance between the planar mesh conductor 4 and both conductor patterns. Two sets of through vias and short vias are provided at the corners of the first conductor pattern 9. As a result, the electromagnetic wave interface 8 can be miniaturized and is capable of providing any and variable directionality and wide-band operation.
The electromagnetic wave interface 8 used for the electromagnetic wave propagation apparatus 100 according to the third embodiment can adjust the power receiving amount in accordance with the dielectric area occupancy. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor 4 is shaped so as to decrease a variation in the dielectric area occupancy.
According to the third embodiment, the power receiving apparatus 23 includes the electromagnetic wave interface 8 and the power receiving circuit 16 and can be integrally mounted on a general-purpose printed substrate. Therefore, miniaturization and cost reduction effects can be promoted.
The third embodiment has described the electromagnetic wave propagation apparatus 100 as a power supply apparatus. The power supply station 7 and the power receiving circuit 16 may be replaced by a communication base station and a receiver, respectively. As a result, the electromagnetic wave propagation apparatus 100 can transmit an electromagnetic wave as a communication signal or a control signal between units, not as the electric power. Obviously, configuration combinations enable both signals to be transmitted simultaneously or under time sharing control. The base station 200 and the terminal 300 may each include a function of transmitting and receiving electromagnetic waves and bidirectionally exchange information.
The fourth embodiment of the invention will be described below.
The electromagnetic wave interface 8 enables miniaturization by decreasing a resonant frequency through the use of capacitance among the first conductor pattern 9, the second conductor pattern 10, and the third conductor pattern 21 that excite three coupling modes. The dielectric substrate 11 includes four layers of conductors. The first conductor pattern 9, the second conductor pattern 10, and the third conductor pattern 21 are formed in order from the conductor layer in contact with the planar propagation medium 5. The circuit mounting conductor 15 is formed as a layer opposite the planar propagation medium 5. The electromagnetic wave interface 8 receives power from the planar propagation medium 5. The power is fed to the power receiving circuit 16 on the circuit mounting conductor 15 through the through via 13. The power receiving circuit 16 rectifies the power. The power is transformed into a specified voltage. The power is then supplied to the unit 22.
In
The embodiment has described the electromagnetic wave interface 8 using three conductor patterns. If four or more conductor patterns are used, the electromagnetic wave interface 8 can provide much wider-band or much more operating frequencies.
According to the embodiment, the short via 12 short-circuits the first conductor pattern 9, the second conductor pattern 10, and the third conductor pattern 21 in the electromagnetic wave interface 8. The operating frequency, the operating band, or the power receiving amount can be adjusted depending on which of the conductor patterns are short-circuited to each other.
The embodiment has described the electromagnetic wave interface 8 used for power reception. The electromagnetic wave interface 8 may be used as the electromagnetic wave input port 6 for power transmission in order to promote miniaturization.
As described above, the electromagnetic wave propagation apparatus 100 according to the fourth embodiment decreases a resonant frequency using the capacitance among the first conductor pattern 9, the second conductor pattern 10, and the third conductor pattern 21 for exciting three coupling modes and the capacitance between the planar mesh conductor 4 and these conductor patterns. The short via 12 short-circuits these conductor patterns. The through via 13 is provided as a power supply point on the diagonal of the first conductor pattern 9. As a result, the electromagnetic wave interface 8 can be miniaturized and is capable of wide-band operation.
The electromagnetic wave interface 8 used for the electromagnetic wave propagation apparatus 100 according to the fourth embodiment can adjust the power receiving amount in accordance with the dielectric area occupancy. The positional dependence of the power receiving amount can be decreased if the planar mesh conductor 4 is shaped so as to decrease a variation in the dielectric area occupancy.
According to the fourth embodiment, the power receiving apparatus 23 includes the electromagnetic wave interface 8 and the power receiving circuit 16 and can be integrally mounted on a general-purpose printed substrate. Therefore, miniaturization and cost reduction effects can be promoted.
The fourth embodiment has described the electromagnetic wave propagation apparatus 100 as a power supply apparatus. The power supply station 7 and the power receiving circuit 16 may be replaced by a communication base station and a receiver, respectively. As a result, the electromagnetic wave propagation apparatus 100 can transmit an electromagnetic wave as a communication signal or a control signal between units, not as the electric power. Obviously, configuration combinations enable both signals to be transmitted simultaneously or under time sharing control. The base station 200 and the terminal 300 may each include a function of transmitting and receiving electromagnetic waves and bidirectionally exchange information.
According to the first through fourth embodiments described above, the short via and the through via may be effective even at positions other than those defined strictly. The short via and the through via take effect accordingly if the positional shift amount is small enough for λg. For example, the short via and the through via may be positioned within the range of ±10 degrees from the diagonal of the first square conductor pattern.
Number | Date | Country | Kind |
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2011-153876 | Jul 2011 | JP | national |