Patent Description:
In order to manage products and the like, a technology using a radio frequency identification (RFID) tag has been used. Such an RFID tag is, for example, provided on an adhesive label and attached to a product via the label. The RFID tag may be issued by an RFID tag issuing apparatus that has an antenna of a tag reader/writer arranged, for example, along a conveyance path for carrying a label within the issuing apparatus. Recently, downsizing of the RFID tag issuing apparatus has been demanded by customers and the like. For this reason, the size of the antenna has been reduced in order to reduce the size of the RFID tag issuing apparatus. However, when the antenna is made smaller, a radio wave emitted therefrom may be weakened and likewise a smaller antenna may not receive signals as well as a larger one.

Hence, there is a need for an antenna capable of suitably emitting a radio wave even when the antenna is small in size.

<CIT> relates to a planar meandering inverted-F antenna. The meandering inverted-F is a planar radiating structure having alternating cutouts along a longitudinal dimension of a planar radiating element or patch which is parallel to a nearly coextensive ground plane.

<CIT> relates to a meandering T-matching structure, a first meandering feed line coupled to the meandering T-matching structure, and a first radiating part coupled to the first meandering feed line. Implementations include a second meandering feed line coupled to the meandering T-matching structure, and a second radiating part coupled to the meandering feed line. A gap may physically separate the first meandering feed line and the second meandering feed line.

<CIT> relates to a kind of small-sized anti-metal broadband label antenna, belonging to microwave technical field.

<CIT> relates to an antenna device performing communications with an identification tag by being connected to a reading device that reads identification information of the identification tag. The antenna device includes a first power feeding unit configured to receive power from the reading device, a resonator that is electromagnetically coupled to the first power feeding unit, the resonator having a predetermined bandwidth including a working frequency of the reading device, and a second power feeding unit that is electromagnetically coupled to the resonator, the second power feeding unit being terminated according to a predetermined resistance value.

<CIT> relates to a near field linear element microstrip antenna configured to read an RFID label such that a localized electric field emitted by the antenna at an operating wavelength resides substantially within a zone defined by the near field. The localized field directs a current distribution along an effective length of the antenna corresponding to a half-wave to a full-wave structure.

According to a first aspect of the invention, it is provided an antenna, comprising a dielectric substrate; a line on a first surface of the dielectric substrate, a maximum width WL1 of the line in a first direction of the first surface being greater than a maximum width WL2 of the line in a second direction orthogonal to the first direction; a ground layer on a second surface of the dielectric substrate, a width WG2 of the ground layer in the second direction being equal to the maximum width WL2 of the line in the second direction; a feeding point at the first end of the line; wherein the termination resistor is at the second end of the line, the termination resistor corresponding to a characteristic impedance of the line; a first end of the line is on a first end side of the first surface, a second end of the line is on the first end side or a second end side of the first surface, and the ground layer avoids a region around the feeding point and the termination resistor.

Optionally, in the antenna according to the first aspect of the invention, the line bends at multiple positions and extends in the first direction multiple times on the first surface of the dielectric substrate.

Optionally, in the antenna according to the first aspect of the invention, the line extends in the first direction, then bends in the second direction, and again extends in the first direction.

Optionally, in the antenna according to the first aspect of the invention, the feeding point and the termination resistor are on the second surface of the dielectric substrate.

Optionally, in the antenna according to the first aspect of the invention, the feeding point and the termination resistor are on the first surface of the dielectric substrate.

Optionally, in the antenna according to the first aspect of the invention, the maximum width WL1 of the line in the first direction is equal to or less than a width W1 of the dielectric substrate in the first direction.

Optionally, in the antenna according to the first aspect of the invention, the maximum width WL2 of the line in the second direction is less than a width W2 of the dielectric substrate in the second direction.

Optionally, in the antenna according to the first aspect of the invention, a width WG1 of the ground layer in the first direction is equal to or greater than the maximum width WL1 of the line in the first direction and equal to or less than the width W1 of the dielectric substrate in the first direction.

Optionally, in the antenna according to the first aspect of the invention, the width WG2 of the ground layer in the second direction is less than a width W2 of the dielectric substrate in the second direction.

Optionally, in the antenna according to the first aspect of the invention, the maximum width WL2 of the line in the second direction and the width WG2 of the ground layer in the second direction are set such that the antenna achieves a predetermined increase in the electric field intensity.

Optionally, in the antenna according to the first aspect of the invention, the increase in the electric field intensity is at least <NUM>% of a difference between the electric field intensity when the width WG2 is equal to the maximum width WL2 and the lowest electric field intensity when the width WG2 is larger than the maximum width WL2, where the maximum difference is defined as <NUM>%.

Optionally, in the antenna according to the first aspect of the invention, the ground layer is in a region of the second surface corresponding to the line on the first surface.

Optionally, the antenna according to the first aspect of the invention further comprises a plurality of via holes formed through the dielectric substrate.

Optionally, it is provided an RFID tag issuing apparatus, comprising an antenna according to the first aspect of the invention;
and a reader/writer configured tc communicate with an RFID tag via the antenna.

Optionally, in the RFID tag issuing apparatus, a first end of the line is on a first end side of the first surface in the first direction, and a second end of the line is on the first end side or a second end side of the first surface in the first direction.

According to one or more embodiments, an antenna comprises a dielectric substrate, a line formed on a first surface of the dielectric substrate, and a ground layer formed on a second surface of the dielectric substrate. A maximum width of the line in a first direction of the first surface is greater than a maximum width of the line in a second direction orthogonal to the first direction. A width of the ground layer in the second direction is equal to the maximum width of the line in the second direction.

Hereinafter, an example embodiment will be described with reference to <FIG>. <FIG> is an explanatory diagram illustrating a configuration of a label paper <NUM> used in an RFID tag issuing apparatus <NUM> according to the embodiment. <FIG> is a block diagram illustrating a configuration of the RFID tag issuing apparatus <NUM>, and <FIG> is an explanatory diagram illustrating some components of the RFID tag issuing apparatus <NUM>. <FIG> is a plan view illustrating the configuration of an antenna <NUM> of the RFID tag issuing apparatus <NUM> from a first surface 31a side, and <FIG> is a plan view showing the configuration of the antenna <NUM> from a second surface 31b side. <FIG> is a cross-sectional view taken along line VI-VI in <FIG>, illustrating the configuration of the antenna <NUM>. <FIG> is an explanatory view illustrating the relationship between a dielectric substrate <NUM>, a line <NUM>, and a ground layer <NUM> of the antenna <NUM>. <FIG> is an explanatory view illustrating a relationship between the line <NUM> and the ground layer <NUM> of the antenna <NUM>, and <FIG> is an explanatory diagram illustrating an example of a relationship between the configuration of the antenna <NUM> and an electric field intensity.

In this embodiment, the antenna <NUM> is applied to the RFID tag issuing apparatus <NUM> that issues an RFID tag <NUM> attached to a label <NUM>.

First, the label paper <NUM> used in the present embodiment will be described with reference to <FIG>. The label paper <NUM> includes a plurality of labels <NUM> and a mount <NUM> to which the plurality of labels <NUM> are initially attached. Each of the plurality of labels <NUM> contains the RFID tag <NUM>. The label paper <NUM>, more particularly the mount <NUM>, may be provided as a roll or a continuous sheet.

Each label <NUM> has a rectangular shape. The plurality of labels <NUM> are attached to one surface of the mount <NUM>. The plurality of labels <NUM> are arranged at a constant interval D in the longitudinal direction. Each label <NUM> has an adhesive surface on a surface facing the mount <NUM>.

Each label <NUM> has one RFID tag <NUM> provided on the adhesive surface. The RFID tag <NUM> includes a film 111a, a tag antenna 111b, and an IC chip 111c. The tag antenna 111b includes, for example, a matching circuit (or a loop unit). The tag antenna 111b and the IC chip 111c are disposed on the film 111a. In this example, the RFID tag <NUM> is a passive tag that does not have a battery.

The attachment position of the RFID tag <NUM> to the label <NUM> can be appropriately set depending on the type of the label paper <NUM>. In the example illustrated in <FIG>, L0 is an entire length of a label <NUM> on the label paper <NUM> along a conveyance direction C, and L1 is a distance along the conveyance direction C from a leading edge (also referred to as a first side end) of the label <NUM> to the RFID tag <NUM> on the label <NUM>. The RFID tag <NUM> is arranged on the label <NUM> at a distance L1 from the leading edge of the label <NUM>. That is, the distance L1 is less than the entire length L0 (i.e., L1 < L0). Further, the RFID tag <NUM> is disposed on the label <NUM> such that the long dimension of the tag antenna 111b in the RFID tag <NUM> is substantially orthogonal to the conveyance direction C.

The mount <NUM>, for example, has a plurality of marks 120a in a region adjacent to the leading edge of the label <NUM> in the conveyance direction C. Each mark 120a corresponds to a head (or a beginning) position of a label <NUM> in the conveyance direction C. The region where the mark is provided is on a main surface of the label paper <NUM> (to which the label <NUM> is attached) and is within a gap between the neighboring labels <NUM>. Each mark 120a has, for example, a width in the conveyance direction C less than the gap between the neighboring labels <NUM>.

The label paper <NUM> in this example has a roll shape formed by winding the mount <NUM> with the plurality of labels <NUM> thereon.

Next, the RFID tag issuing apparatus <NUM> according to the present embodiment will be described. As shown in <FIG> and <FIG>, the RFID tag issuing apparatus <NUM> comprises a conveyance roller <NUM>, a platen roller <NUM>, a motor <NUM>, a motor driver <NUM>, a mark sensor <NUM>, a sensor signal input unit <NUM>, an antenna <NUM>, a reader/writer <NUM>, a print head <NUM>, a head driver <NUM>, a movement mechanism driver <NUM>, a display <NUM>, an input unit <NUM>, a communication interface (I/F) <NUM>, a storage unit <NUM>, and a processor <NUM>.

The conveyance roller <NUM> comprises, for example, a pair of rollers 11a and 11b. The conveyance roller <NUM> conveys the roll-shaped label paper <NUM> along a conveyance path in the conveyance direction C. The conveyance roller <NUM> may comprise a plurality of rollers provided on the conveyance path. One of the rollers 11a and 11b is, for example, a drive roller which is driven by the motor <NUM>, and the other roller is a driven roller.

The platen roller <NUM> rotates to convey the label paper <NUM> along the conveyance path in the conveyance direction C. The platen roller <NUM> is arranged on the second side of the conveyance roller <NUM> and the mark sensor <NUM> in the conveyance path. For example, the platen roller <NUM> is driven to rotate by the motor <NUM>. The platen roller <NUM> may comprise a plurality of rollers arranged in a similar manner to the above configuration.

The motor <NUM> is mechanically connected to the conveyance roller <NUM> and to the platen roller <NUM>. The motor <NUM> rotates the conveyance roller <NUM> and the platen roller <NUM>. In one embodiment, the motor <NUM> rotates the roller 11a of the conveyance roller <NUM> and the platen roller <NUM> in the direction indicated by the arrow in <FIG> to convey the label paper <NUM> along the conveyance path.

The motor driver <NUM> (see <FIG>) controls the rotation of the motor <NUM>. In addition, the motor driver <NUM> controls the forward rotation and the reverse rotation of the motor <NUM>. The motor driver <NUM> controls the motor <NUM> in the normal, forward rotation, thereby rotating the conveyance roller <NUM> and the platen roller <NUM> in the direction indicated by the arrow in <FIG>, and transporting the label paper <NUM> in the conveyance direction C.

The mark sensor <NUM> is provided facing the conveyance path. The mark sensor <NUM> is arranged on the downstream side of the conveyance roller <NUM> and on the upstream side of the platen roller <NUM> along the conveyance path. The mark sensor <NUM> optically detects, for example, the mark 120a on the mount <NUM>. The mark sensor <NUM> scans the surface of the label paper <NUM> being conveyed in the conveyance direction C and detects the mark 120a. The mark sensor <NUM> outputs the detected information as a signal to the sensor signal input unit <NUM>.

The sensor signal input unit <NUM> can be connected to various sensors including the mark sensor <NUM>. The sensor signal input unit <NUM> receives signals from the various sensors and outputs the signals to the processor <NUM>. Here, the various sensors include an open/close sensor for detecting opening and closing of a member or a component of the RFID tag issuing device <NUM> that will be opened or closed, for example when replacing the label paper <NUM>. Such a member or component is, for example, a cover, a door, a lid, or the like. An example of an open/close sensor may be an optical sensor that turns on in response to closing or opening of the above member. In another example, the open/close sensor may be a mechanical switch that switches on and off in response to closing and opening of the member. The open/close sensor may comprise a detection unit that detects closing and opening of the openable member that is opened and closed to exchange the RFID tags <NUM> to be conveyed in the RFID tag issuing apparatus <NUM>.

As shown in <FIG>, the antenna <NUM> includes a dielectric substrate <NUM>, a line <NUM>, a ground layer <NUM>, a feeding point <NUM> (also referred to as a power feeding point in some contexts), and a termination resistor <NUM>.

The dielectric substrate <NUM> is formed of a dielectric material. The dielectric substrate <NUM> has a rectangular plate shape. In one example, the dielectric substrate <NUM> has a rectangular plate shape in which a width W1 in a first direction is greater than a width W2 in a second direction along a main surface direction of the dielectric substrate <NUM> orthogonal to the first direction. The rectangular plate shape is thus long in one direction. In addition, the dielectric substrate <NUM> has a plurality of via holes 31c, each of which penetrates through a first surface 31a as one main surface and a second surface 31b as another main surface of the dielectric substrate <NUM>. The via holes 31c are disposed on both ends of the line <NUM>.

The line <NUM> is formed on the first surface 31a of the dielectric substrate <NUM>. A first end of the line <NUM> is disposed on one side of the dielectric substrate <NUM>, and the second end of the line <NUM> is disposed on the other side of the dielectric substrate <NUM> opposite in in the first direction. Here, the first direction refers to a direction along the main surface of the dielectric substrate <NUM>. In the present embodiment, the first direction is the longitudinal direction (longer dimension) of the dielectric substrate <NUM>.

As shown in <FIG>, for the line <NUM>, the maximum width WL1 in the first direction is set to be greater than the maximum width WL2 in a second direction orthogonal to the first direction along the main surface of the dielectric substrate <NUM>. For example, the maximum width WL1 of the line <NUM> in the first direction is set to be equal to or less than the width W1 of the dielectric substrate <NUM> in the first direction, and the maximum width WL2 of the line <NUM> in the second direction is less than the width W2 of the dielectric substrate <NUM> in the second direction.

In one example, as shown in <FIG>, and <FIG>, the line <NUM> has a shape that bends <NUM> degrees at four positions, turns two times, and extends in the first direction in three portions.

In the depicted example, the line <NUM> extends linearly in the first direction from a first end side towards a second end side of the dielectric substrate <NUM>. The line <NUM> then bends <NUM> degrees, extends briefly in the second direction, then bends another <NUM> degrees to extend again in the first direction (this time back towards the first end side of the dielectric substrate <NUM>). The line then bends <NUM> degrees, extends briefly again in the second direction. The line <NUM> then bends another <NUM> degrees to extend again in the first direction (this time back towards the second end side.

The ground layer <NUM> is provided on a second surface 31b. The second surface 31b is the other main surface of the dielectric substrate <NUM>. The ground layer <NUM> is provided, for example, in the region of the second surface 31b corresponding to the line <NUM> provided on the first surface 31a. The ground layer <NUM> has a rectangular shape.

As shown in <FIG>, when the feeding point <NUM> and the termination resistor <NUM> are provided on the second surface 31b of the dielectric substrate <NUM>, the ground layer <NUM> is provided so as to avoid the region around the feeding point <NUM>, the termination resistor <NUM>, and the via hole 31c. Alternatively, if the feeding point <NUM> and the termination resistor <NUM> are provided on the first surface 31a of the dielectric substrate <NUM>, for example, the ground layer <NUM> may be provided in a region around the via hole 31c of the first surface 31a of the dielectric substrate <NUM> and the via hole 31c.

For the ground layer <NUM>, its width WG1 in the first direction is set to be equal to or greater than the maximum width WL1 of the line <NUM> and also is set to be equal to or less than the width W1 of the dielectric substrate <NUM> in the first direction. In the present embodiment as shown in <FIG>, the ground layer <NUM> has the width WG1 that is the same width as the width W1 of the dielectric substrate <NUM>. Further, the ground layer <NUM> has a width WG2 in the second direction that is the same width as the maximum width WL2 of the line <NUM> in the second direction and is less than the width W2 of the dielectric substrate <NUM> in the second direction.

As depicted in <FIG>, and <FIG>, the width WG2 of the ground layer <NUM> and the width WL2 of the line <NUM> are the same, but the present disclosure is not limited to this and these widths need not be exactly equal to one another, but rather may be substantially or approximately equal to each other without being exactly equal to one another.

Furthermore, in some examples, the width WG2 the width WG2 can be somewhat greater than the maximum width WL2 of the line <NUM>. Thus, in this context, "substantially equal" encompasses the width WG2 being larger than the maximum width WL2, for example, is the width WG2 relative to the maximum width WL2 being a dimension for which an increase in electric field intensity of antenna <NUM> is <NUM>% or more.

In this context, a "<NUM>% increase in electric field intensity " refers to <NUM>% of the total change between the electric field intensity from the antenna <NUM> when the width WG2 is exactly equal to the maximum width WL2 and the lowest electric field intensity of the antenna <NUM> when the width WG2 of the ground layer <NUM> is made increasingly greater than the maximum width WL2.

An "increase in electric field intensity" will be described by using an example of a relationship between the configuration of the antenna <NUM> and the electric field intensity illustrated in <FIG> is an explanatory diagram schematically illustrating a relationship between the maximum width WL2 of the line <NUM> and the width WG2 of the ground layer <NUM> in the second direction, and <FIG> is an explanatory diagram illustrating the calculated performance of the different configurations of the antenna <NUM>, (that is, the changes in configuration with respect to the relationship between the maximum width WL2 of the line <NUM> and the width WG2 of the ground layer <NUM>) according to the electric field intensity calculated by an electromagnetic field simulator.

Note that the conditions for calculating the electric field intensity in the electromagnetic field simulator according to the present example are the following. The width W1 of the dielectric substrate <NUM> is <NUM>, the width W2 of the dielectric substrate <NUM> is <NUM>, and the maximum width WL2 of the line <NUM> is <NUM>. Further, the width WG2 of the ground layer <NUM> is set as WG2 = WL2 + 2d, and d is increased in increments of <NUM> from d = <NUM> to d = <NUM>, and the electric field intensity at a position separated by <NUM> from the center of the antenna <NUM> is calculated.

As illustrated in <FIG>, the electric field intensity of the antenna <NUM> in the present example has the highest electric field intensity when d = <NUM>, i.e., WG2 = WL2, and the electric field intensity decreases as d increases. After d = <NUM>, change in the electric field intensity becomes substantially level, and at d = <NUM>, it reaches the smallest value.

Therefore, in this context, the "increase in electric field intensity" is taken as the difference between the electric field intensity at d = <NUM> and the electric field intensity at d = <NUM> in the present example. Thus, the "<NUM>% increase in electric field intensity" means <NUM>% of that overall (total) difference. For example, based on the calculation, d is around <NUM> when the electric field intensity becomes <NUM>% of the total difference between the electric field intensity at d = <NUM> and the electric field intensity at d = <NUM>.

In the present example, the width WG2 of the ground layer <NUM> with respect to the maximum width WL2 of the line <NUM> that achieves the "increase in electric field intensity" of <NUM>% or more has the range of <NUM> ≤ WG2 ≤ <NUM>. This indicates that the width WG2 of the ground layer <NUM> is about <NUM>% to <NUM>% with respect to the maximum width WL2 of the line <NUM>.

As described above, the width WG2 of the ground layer <NUM> in the second direction being the same as the maximum width WL2 of the line <NUM> in the second direction is allowed to be substantially equal to the maximum width WL2 of the line <NUM> so long as the increase in electric field intensity is equal to or greater than <NUM>%.

Turning now to other features of the antenna <NUM> as shown in <FIG>, the antenna <NUM> further comprises the feeding point <NUM> provided at a position adjacent to the via hole 31c of the second surface 31b of the dielectric substrate <NUM> in the first direction. The feeding point <NUM> is connected to one end of the line <NUM> through the via hole 31c. A part of the feeding point <NUM> is connected to the ground layer <NUM> at the second surface 31b of the dielectric substrate <NUM>.

Further, in the present embodiment as shown <FIG>, the antenna <NUM> comprises the termination resistor <NUM> provided at a position adjacent to the other via hole 31c of the second surface 31b of the dielectric substrate <NUM> in the first direction. The termination resistor <NUM> is connected to the other end of the line <NUM> through the via hole 31c. The termination resistor <NUM> is, for example, partially connected to the ground layer <NUM> on the second surface 31b of the dielectric substrate <NUM>. The termination resistor <NUM> is set to a resistance value corresponding to the characteristic impedance of the line <NUM>.

Such antennas <NUM> are, for example, arranged so as to be spaced apart from each other in a direction orthogonal to both the conveyance direction C and the width direction of the mount <NUM> from the conveyance path. Note that the distance away from the conveyance path of the antenna <NUM> is appropriately set according to the electric field intensity of the antenna <NUM>. For example, the antenna <NUM> is disposed to be spaced apart from the conveyance path by <NUM>. The antenna <NUM> is arranged in a posture in which the first direction is orthogonal to the conveyance path. Further, the antenna <NUM> is disposed at a position where the center of the antenna <NUM> in the first direction is a center in the width direction of the conveyance path. That is, the RFID tag <NUM> passes along the conveyance path and passes through the center side in the first direction of the antenna <NUM>.

The reader/writer <NUM> controls the antenna <NUM> and performs data wireless communication with the RFID tag <NUM>. In one example, the reader/writer <NUM> causes the antenna <NUM> to emit a radio wave (or radio waves) and receives the radio waves from the antenna <NUM>. In this way, the reader/writer <NUM> communicates with the RFID tag <NUM> and writes and reads the RFID tag <NUM>. In one example, the reader/writer <NUM> causes the antenna <NUM> to emit an unmodulated wave as a radio wave in order to perform wireless communication with the RFID tag <NUM>. The RFID tag <NUM> that has received the unmodulated wave starts up and transmits a response wave to the antenna <NUM>. Therefore, the reader/writer <NUM> receives the response wave through the antenna <NUM> and communicates with the RFID tag <NUM>. In addition, for example, when writing data to the RFID tag <NUM>, the reader/writer <NUM> performs amplitude modulation on a carrier wave that is emitted from the antenna <NUM> to encode the written data.

The print head <NUM> is arranged to face the platen roller <NUM> with the conveyance direction C interposed therebetween. The print head <NUM> is connected to the head driver <NUM>. The print head <NUM> prints on a printing surface of the conveyed label <NUM>, that is, a surface opposite to the surface on which the RFID tag <NUM> is provided.

The head driver <NUM> drives the print head <NUM> based on print data and the like to print on the printing surface of the label <NUM>. The movement mechanism driver <NUM> moves the print head 15A back and forth along one direction adjacent to the label paper <NUM> transported through the conveyance path.

Note that the display <NUM> may further include an LED or the like and may have a speaker or the like capable of notifying information by sound.

The input unit <NUM> is, for example, a touch panel provided in or integrated with the display <NUM>. Note that the input unit <NUM> may be a keyboard, a pointing device, a touch panel, or the like provided in a housing of the RFID tag issuing apparatus <NUM>.

The communication interface <NUM> is an interface for communicating with an external device or control device. The communication interface <NUM> receives data to be written to the RFID tag <NUM> and print data to be printed on the label <NUM> from the external or control device. In addition, the communication interface <NUM> transmits data such as issuance result data to the external or control device.

The storage unit <NUM> stores a program (or programs) required to control the RFID tag issuing apparatus <NUM>, and various kinds of data, such as print data and issuance result data. The storage unit <NUM> is, for example, a Read Only Memory (ROM), a Random Access Memory (RAM), a Solid State Drive (SSD), or the like. The processor <NUM> is, for example, a central processing unit (CPU). The processor performs various operations on data or the like based on the program(s) stored in the storage unit <NUM> or the memory. By executing the program(s), the processor functions as a control unit or controller that is capable of executing various operations according to program instructions.

The processor <NUM> is connected to the motor driver <NUM>, the sensor signal input unit <NUM>, the reader/writer <NUM>, the head driver <NUM>, the movement mechanism driver <NUM>, the display <NUM>, the input unit <NUM>, the communication interface <NUM>, and the storage unit <NUM>. The processor <NUM> controls each configuration in accordance with the signal input from the sensor signal input unit <NUM>, the program stored in the storage unit <NUM>, and the like, thereby realizing the function of the RFID tag issuing apparatus <NUM>. For example, the processor <NUM> controls the reader/writer <NUM> to control reading and writing of the RFID tag <NUM> via the antenna <NUM>.

According to the RFID tag issuing apparatus <NUM> configured as described above, the width WG2 of the ground layer <NUM> of the antenna <NUM> is set to be the same width as the maximum width WL2 of the line <NUM> in the second direction, and thus, as illustrated in <FIG>, the electric field intensity of the antenna <NUM> can be increased.

As a result, even when the antenna <NUM> is downsized, it is possible to achieve an electric field intensity similar to that of the antenna <NUM> before the downsizing. This enables the antenna <NUM> to suitably emit a radio wave. Even if the RFID tag issuing apparatus <NUM> is miniaturized, the antenna <NUM> can still perform the desired communication with the RFID tag <NUM>. Consequently, effective downsizing of the antenna <NUM> and the RFID tag issuing apparatus <NUM> becomes possible.

As described above, according to the antenna <NUM> and the RFID tag issuing apparatus <NUM> according to the present embodiment, it is possible to suitably emit a radio wave (or radio waves) even when the antenna <NUM> and the RFID tag issuing apparatus <NUM> are made smaller.

Note that the antenna <NUM> and the RFID tag issuing apparatus <NUM> are not limited to the above-described embodiments and examples. In general, so long as the maximum width WL1 of the line <NUM> in the first direction is set to be larger than the maximum width WL2 of the line <NUM> in the second direction and also the width WG2 of the ground layer <NUM> in the second direction is set to be the same as the maximum width WL2 of the line <NUM> in the second direction, the line <NUM> is not limited to the shape of the above-described embodiment. Hereinafter, various examples of modifications of the line <NUM> will be described with reference to <FIG>. For simplicity of explanation, the via hole 31c, the feeding point <NUM>, and the termination resistor <NUM> are omitted from the depicted antennas in <FIG> and <FIG>.

First, an antenna 17A according to a first modified example will be described with reference to <FIG>. As shown in <FIG>, the antenna 17A includes a line 32A formed in a linear shape and a ground layer 33A formed in a rectangular shape having the same shape as that of the line 32A. The line 32A has one end disposed on one end side (a first end side) of the dielectric substrate 31A in the first direction= and another end disposed on the opposite end side (or second end side) of the dielectric substrate 31A in the first direction. That is, the line 32A extends linearly along the first direction from the first end side to the second end side of the dielectric substrate <NUM>.

In a similar manner to the antenna <NUM> shown in <FIG>, in the antenna 17A a width of the line 32A in the second direction (a maximum width) and a width of the ground layer 33A in the second direction are equal to each other. With this configuration, the antenna 17A can increase the electric field intensity and can suitably emit radio waves even if the antenna 17A is made smaller.

Next, an antenna 17B according to a second modified example will be described with reference to <FIG>. As shown in <FIG>, a line 32B of the antenna 17B first extends from the first end side to the center side of the dielectric substrate 31B in the first direction. It then bends <NUM>° and extends in the second direction. Further, the line 32B bends <NUM>° and extends toward the second end side of the dielectric substrate 31B in the first direction. The ground layer 33B of the antenna 17B has its width in the second direction equal to the maximum width of the line 32A in the second direction.

Thus, in a similar manner to the antenna <NUM> shown in <FIG>, the antenna 17B can increase the electric field intensity and can suitably emit radio waves even if the antenna 17B is made small.

Next, an antenna 17C according to a third modified example will be described with reference to <FIG>. As shown in <FIG>, the antenna 17C includes a line 32C and a ground layer <NUM>. The line 32C extends along the first direction, folds back by bending <NUM>° at two positions, and extends again in the first direction. Both ends of the line 32C are on the first end side of the dielectric substrate <NUM> in the first direction. The ground layer 33C has a width in the second direction equal to the maximum width of line 32C in the second direction.

More specifically, the line 32C of the antenna 17C extends linearly along the first direction from the first end side of the dielectric substrate 31C in the first direction (that is the same position as the first end side of the dielectric substrate 31C in the second direction) toward the second end side of the dielectric substrate 31C in the first direction. The line 32C then bends <NUM>° and extends in the second direction. The line 32C bends <NUM>° again and extends back toward the first end side of the dielectric substrate <NUM> in the first direction. Finally, the line 32C ends at the first end side of the first direction.

In a similar manner to the antenna <NUM> shown in <FIG>, the antenna 17C having a configuration as described above can increase the electric field intensity and can suitably emit radio waves even if the antenna 17C is made smaller.

Next, an example of a relationship between the configuration of the antenna 17C the electric field intensity as illustrated in <FIG> will be described. In <FIG>, the relationship between the configuration of the antenna 17C (that is, the configuration of the maximum width WL2 of the line <NUM> in the second direction and the width WG2 of the ground layer <NUM> in the second direction) and the electric field intensity calculated by the electromagnetic field simulator.

Note that the conditions for calculating the electric field intensity by the electromagnetic field simulator according to the present example are the following. The width W1 of the dielectric substrate <NUM> in the first direction is set at <NUM>, the width W2 of the dielectric substrate <NUM> in the second direction is set at <NUM>, and the maximum width WL2 of the line <NUM> in the second direction is set at <NUM>. Further, the width WG2 of the ground layer <NUM> in the second direction is set as WG2 = WL2 + 2d, and d is incremented by <NUM> from d = <NUM> to d = <NUM>, and the electric field intensity at a position separated by <NUM> from the center of the antenna <NUM> was calculated.

As shown in <FIG>, the antenna 17C of <FIG> using the line 32C as described above achieves the same effects as those achieved by the antenna <NUM> of <FIG>. When d = <NUM> (that is, WG2 = WL2), the electric field intensity becomes the highest, and as d increases, the electric field intensity decreases. After d = <NUM>, the electric field intensity becomes substantially level. The electric field intensity reaches the smallest value at d = <NUM>. Therefore, the difference between the electric field intensity at d = <NUM> and the electric field intensity at d = <NUM> is considered to correspond to the <NUM>% increase in the electric field intensity. The width at which the increase in electric field intensity is <NUM>% or more is about d = <NUM>.

In this example, the width WG2 of the ground layer 33C with respect to the maximum width WL2 of the line 32C in which the "increase in electric field intensity" is <NUM>% or more is in the range of <NUM> ≤ WG2 ≤ <NUM>. Also, as is apparent from the results of the calculations, the electric field intensity can be improved by making the maximum width WL2 of the line such as the lines <NUM>, 32A, 32B, and 32C (hereinafter collectively referred to as the line <NUM>) and the width WG2 of the ground layer such as the ground layers <NUM>, 33A, 33B, and 33C (hereinafter collectively referred to as the ground layer <NUM>)equal to each other, regardless of the shape of the line <NUM> of the antenna.

While the dielectric substrates <NUM>, 31A, 31B, and 31C (hereinafter collectively referred to as the dielectric substrate <NUM>) have been illustrated as having a rectangular plate shape elongated in one direction, its shape is not limited thereto. For example, an antenna 17D according to another embodiment as illustrated in <FIG> has a dielectric substrate 31D of a square plate shape.

In the embodiment shown in <FIG>, the antenna <NUM> has a configuration in which the feeding point <NUM> and the termination resistor <NUM> are provided on the second surface 31b of the dielectric substrate <NUM>. The configuration is not limited thereto. For example, in the antenna 17D as shown in <FIG> according to another embodiment, a feeding point 34D (or simply referred to as a feeding point) and a termination resistor 35D are provided on the first surface 31Da of the dielectric substrate 31D.

In this case, the ground layer 33D may be provided in the area around the via hole 31Dc of the first surface 31Da, leaving an open space for the via hole 31Dc, and the feeding point 34D and the termination resistor 35D may be connected to the ground layer 33D.

As another example of the antenna <NUM>, one of the feeding point <NUM> (or 34D) and the termination resistor <NUM> (or 35D) may be provided on the first surface 31a of the dielectric substrate <NUM>, and the other of the two may be provided on the second face 31b of the dielectric substrate <NUM>.

In the embodiments and examples as shown in <FIG>, the antenna <NUM> has been described to have the width W1 of the dielectric substrate <NUM> and the width WG1 of the ground layer <NUM> are set to be equal to each other. The configuration, however, is not limited thereto. For example, as shown in <FIG>, if the feeding point 34D and the termination resistor 35D are connectable to the ground layer 33D, the width WG1 of the ground layer 33D may be equal to or greater than the maximum width WL1 of the line 32D and smaller than the width W1 of the dielectric substrate 31d.

While in the above-described embodiments and examples, the antenna <NUM> has been described as having the configuration applicable to the RFID tag issuing apparatus <NUM>, its application is not limited thereto. The antenna <NUM> can be applied to various types of the RFID tag issuing apparatus or other devices suitable for accommodating or handling the antenna <NUM>. For example, the antenna <NUM> can be applied to a device that does not perform printing on the label <NUM> of the label paper <NUM>, or alternatively, the RFID tag issuing apparatus <NUM> may not perform printing on the label <NUM>.

According to the antenna and the RFID tag issuing apparatus of the above-described embodiments and examples, it is possible to suitably emit a radio wave even if the antenna is made smaller.

Claim 1:
An antenna (<NUM>), comprising:
a dielectric substrate (<NUM>);
a line on a first surface of the dielectric substrate (<NUM>), a maximum width (WL1) of the line in a first direction of the first surface being greater than a maximum width (WL2) of the line in a second direction orthogonal to the first direction;
a ground layer (<NUM>) on a second surface of the dielectric substrate (<NUM>), a width (WG2) of the ground layer (<NUM>) in the second direction being equal to the maximum width (WL2) of the line in the second direction;
a feeding point at the first end of the line;
wherein:
a termination resistor (<NUM>) at the second end of the line, the termination resistor corresponding to a characteristic impedance of the line;
a first end of the line is on a first end side of the first surface,
a second end of the line is on the first end side or a second end side of the first surface; and
the ground layer (<NUM>) avoids a region around the feeding point and the termination resistor (<NUM>).