JP2001024426A - Antenna element and circularly polarized antenna system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact rectangular antenna element suitable for being built-in portable equipment and a circularly polarized wave antenna device using the antennal element. SOLUTION: Two orthogonally crossing patch electrodes 3 and 7 are arranged on the upper face of an almost rectangular dielectric substrate 2 in the longitudinal direction, and a ground electrode 6 is arranged on the lower face of the dielectric substrate 2. A first short circuit electrode 4 for electrically connecting one patch electrode 3 with the ground electrode 6 is arranged on the longitudinal side face of the dielectric substrate 2, and a second short circuit electrode 8 for electrically connecting the other patch electrode 7 with the ground electrode 6 is arranged on the rectangular side face of the dielectric substrate 2. Power supply electrodes 5 and 9 electrically connected with the patch electrodes 3 and 7 are arranged on the side faces on which the short circuit electrodes 4 and 8 of the patch electrodes 3 and 7 are arranged. Then, two orthogonally crossing 1/4 wavelength type one side short circuit type microstrip antennas 1a and 1b are mutually combined so that circularly polarized waves can be generated. In this case, the dimension can be reduced to at most an area ratio which is 1/2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circularly polarized antenna mounted on a portable device or the like and receiving a radio wave transmitted from a navigation satellite or the like.

[0002]

2. Description of the Related Art In recent years, satellite navigation devices that are built into portable equipment, receive radio waves from navigation satellites, and determine their current position have become widespread.
A device that automatically transmits its own position to a base station during an emergency communication is also becoming popular.

As satellite navigation, GPS (Global Positio
A system called right-handed circular polarization is used in a system called multiple GPs orbiting the earth.
In order to efficiently receive a radio wave from the S satellite, an antenna that has a flat gain over a wide angle and can receive a right-handed circularly polarized wave well is desired. Further, since the antenna is built in a portable device, it is desired that the outer shape of the antenna be as small as possible.

A conventional circularly polarized antenna device 40 shown in FIG.
0 is based on a half-wave type open-ended microstrip patch antenna.
1 and the low-noise amplifier 50 are combined. A rectangular patch electrode 43 is formed on one surface of a dielectric substrate 42 whose upper and lower surfaces are substantially square, and the ground electrode 4
4 are formed. Diagonal corner 43 of patch electrode 43
By notching a, circularly polarized waves are generated. The patch electrode 43 and the ground electrode 44 are generally formed by printing a silver paste or a copper paste on the dielectric substrate 42, respectively.

A through hole 46 is provided in the dielectric substrate 42, and the ground electrode 44 is removed in the vicinity of the through hole 46 in the ground electrode 44 formed on the other surface of the dielectric substrate 42. A removing unit 47 is provided. Patch electrode 4
Power is supplied to the power supply 3 by inserting a power supply pin 45 into the through hole 46 and connecting the power supply pin 45 to the patch electrode 43 by soldering or the like. The position of the feed pin 45 is set such that the input impedance of the antenna element 41 is, for example, 50 ohms.

[0006] The low-noise amplifier 50 uses H as a semiconductor element.
It comprises a first-stage amplifier 52 using an EMT or the like, a band-pass filter 53, a buffer amplifier 54, and the like. The feed pin 45 of the circularly polarized antenna 41 is connected to the input terminal 51 of the low noise amplifier 50. Output terminal 5 of low noise amplifier 50
Reference numeral 5 is connected to an input terminal of a receiver (not shown) via a coaxial cable or the like.

The length dimensions K and L of each side of the patch electrode 43 of the conventional antenna element 41 shown in FIG. 4 are determined by the relative permittivity εr and the thickness dimension H2 of the dielectric substrate 42.
For example, when resonance is obtained at a GPS frequency of 1575.42 MHz, the lengths K and L of one side of the patch electrode 43 and the length W of one side of the dielectric substrate 42 relative to the relative dielectric constant εr
2, L2 is as shown in Table 1 when the upper surface and the lower surface are square. However, the material of the dielectric substrate 42 is dielectric ceramic, and the thickness dimension H2 is 4 mm.

[Table 1]

As described above, it can be seen that the antenna element 41 is reduced in size as the dielectric substrate 42 having a large relative permittivity εr is used. A dielectric ceramic having a relative dielectric constant εr of about 20 to 90 generally has a dielectric loss tangent tan.
Since δ is about 1 × 10 ⁻⁴ or less, the radiation efficiency of the antenna becomes about 90% or more. In the case of receiving radio waves, the required gain is obtained, and there is no problem with circular polarization characteristics.

In the above, an example of the dimensions of the antenna element 41 using the dielectric substrate 42 up to the case where the relative dielectric constant εr is 90 has been shown. However, a dielectric ceramic having a higher relative dielectric constant εr is used as the dielectric substrate 42. By using the antenna element 41, the antenna element 41 is further miniaturized as compared with the case where the relative dielectric constant εr is 90. However, in general, in a dielectric ceramic having a relative dielectric constant εr exceeding about 100, the dielectric loss tangent t
An δ tends to increase, lowering the radiation efficiency of the antenna and making it impossible to obtain the required gain. In addition, since a slight dimensional error of the patch electrode 43 and the like greatly affects the resonance frequency, the production yield is greatly deteriorated.

[0010]

As described above,
In the antenna element 41 of the conventional circularly polarized antenna device 400, as the dielectric substrate 42 having a large relative permittivity εr is used, the antenna element 41 is reduced in size and approximated to a form suitable for being incorporated in a portable device. Can be done. However, the circularly polarized antenna device 400 for GPS reception is used.
Is considered to be built into the upper end of the mobile phone with the patch electrode 43 facing upward, the thickness direction of the mobile phone corresponds to the length dimension W2 or D2 of the antenna element 41. Therefore, in the antenna element 41 using the dielectric substrate 42 having a practical relative permittivity εr, the length dimension W2 or D2 becomes larger than the thickness required for a recent small and thin mobile phone, The design of the mobile phone may be damaged.

The present invention has been made to solve the above problems, and is suitable for being incorporated in a portable device.
It is an object of the present invention to provide a small, rectangular parallelepiped circularly polarized antenna element.

[0012]

An antenna element according to the present invention comprises a substantially rectangular parallelepiped dielectric substrate, and two patch electrodes provided in parallel with each other in the longitudinal direction of the upper surface of the dielectric substrate and orthogonal to each other. A ground electrode provided on the lower surface of the dielectric substrate; a first short-circuit electrode provided on a longitudinal side surface of the dielectric substrate for electrically connecting one of the patch electrodes to the ground electrode; A second short-circuit electrode provided on the side surface in the hand direction and electrically connecting the other of the patch electrodes to the ground electrode, and a second short-circuit electrode provided on the side on which the short-circuit electrode of each patch electrode is provided, corresponding to each patch electrode; , And a power supply electrode electrically connected to each patch electrode. According to such an antenna element, two quarter-wavelength one-side short-circuited microstrip antennas which are orthogonal to each other are formed, and by combining these two one-sided short-circuited microstrip antennas with each other, circularly polarized waves are formed. Can be generated. In addition, the dimensions of these one-side short-circuit type microstrip antennas can be reduced to one quarter in area ratio with respect to the dimensions of the conventional half-wave resonance type open-ended microstrip antenna. The area ratio can be reduced to one half of the area ratio. Forming each feed electrode extending from the side surface of the dielectric substrate to the lower surface on which the installation electrode is provided is necessary when mounting the antenna element on a circuit board for forming a low noise amplifier or the like. It is preferable because it can be mounted in the same process as the parts.

Another antenna element according to the present invention is provided with a substantially rectangular parallelepiped dielectric base and a juxtaposition in the longitudinal direction of the upper surface of the dielectric base.
Two patch electrodes provided at right angles to each other, a ground electrode provided on the lower surface of the dielectric substrate, and one of the patch electrodes and the ground electrode provided on the longitudinal side surface of the dielectric substrate. A second short-circuit electrode provided on the lateral side surface of the dielectric substrate and electrically connecting the other of the patch electrodes to the ground electrode;
Each of the through-holes of the dielectric substrate formed from each patch electrode toward the ground electrode is provided corresponding to each patch electrode, and includes a feed electrode electrically connected to each patch electrode. is there. According to such an antenna element, circularly polarized waves can be generated by combining two one-side short-circuited microstrip antennas formed orthogonal to each other. And the size can be reduced to half the area ratio as compared with the conventional case. Further, since the power supply electrode is provided so as to penetrate the dielectric substrate, the power supply electrode can be formed as short as possible, and desired power supply can be performed. It is preferable to use the power supply electrode as the power supply pin because loss in the power supply electrode can be reduced and a strong connection between the antenna element and the circuit board can be secured.

In the circularly polarized antenna device according to the present invention, the 90 ° phase shifting means is electrically connected to one of the feeding electrodes of the antenna element, and the other of the 90 ° phase shifting means and the feeding electrode is fed. The power combining means is electrically connected between the electrodes. According to such a circularly polarized antenna device, a small circularly polarized antenna device suitable for being built in a portable device can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the circularly polarized antenna device of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of a circularly polarized antenna device according to the present invention. A circularly polarized antenna device 100 is configured by combining an antenna element 1 and a low noise amplifier 10. A patch electrode 3 and a patch electrode 7 are formed on the upper surface of a substantially rectangular parallelepiped dielectric base 2 constituting the antenna element 1 at positions orthogonal to each other along one axis, that is, the y-axis in FIG. A ground electrode 6 is formed on substantially the entire lower surface of the dielectric substrate 2.

The patch electrodes 3 and 7 have substantially the same shape. The patch electrode 3 is located at the front end of FIG.
a, 3b and 3c, and the electrodes 3a and 3
The portion b is connected to the ground electrode 6 via the short-circuit portions 4a and 4b of the short-circuit electrode 4 on the front side. The electrode 3c is connected to the side surface 5a constituting the power supply electrode 5, and
Is connected to a lower surface portion 5b constituting a power supply electrode 5 formed on the lower surface of the. In the vicinity of the lower surface portion 5b of the power supply electrode 5, the ground electrode 6 is removed. By forming the various electrodes in this manner, a one-side short-circuit type microstrip antenna 1a is formed on the left side of the antenna element 1 in FIG. The electrode 3c of the patch electrode 3 is set so that the input impedance of the one-side short-circuit type microstrip antenna 1a is, for example, 50 ohms.

On the other hand, the patch electrode 7 is divided into three electrodes 7a, 7b and 7c at the right end in FIG.
And 7b are short-circuit portions 8a and 8b of the short-circuit electrode 8 on the right side.
Is connected to the ground electrode 6 via the. The electrode 7c is connected to the side surface 9a of the power supply electrode 9, and further connected to the lower surface 9b of the power supply electrode 9 formed on the lower surface of the dielectric substrate 2. In the vicinity of the lower surface 9b of the power supply electrode 9, the ground electrode 6 is removed. By forming the various electrodes in this manner, a one-side short-circuit type microstrip antenna 1b is formed on the right side of the antenna element 1 in FIG. The electrode 7c of the patch electrode 7 is set so that the input impedance of the one-side short-circuit type microstrip antenna 1b is, for example, 50 ohms.

The low noise amplifier 10 includes a power combining means 13,
It comprises a 90 ° phase shifting means 14, a first-stage amplifier 15 using HEMT or the like as a semiconductor element, a band-pass filter 16, a buffer amplifier 17, and the like. The power combining means 13 has a function of combining two input signals with equal amplitude and in phase.
The feed electrode 5 of the antenna element 1 is connected to the input terminal 11 of the low-noise amplifier 10, and the feed electrode 9 of the antenna element 1
Is connected to the input terminal 12 of the low noise amplifier 10. An output terminal 18 of the low noise amplifier 10 is connected to an input terminal of a receiver (not shown) via a coaxial cable or the like.

The antenna element 1 is composed of two one-side short-circuit type microstrip antennas 1a and 1b.
The electric field received by the one-side short-circuited microstrip antenna 1a is in the xz plane in the coordinate system shown in FIG. 1, and the electric field received by the one-side short-circuited microstrip antenna 1b is y in the coordinate system shown in FIG. The -z plane is the main direction. That is, the polarization planes differ by 90 °. Also, one-side short-circuit type microstrip antenna 1b
Is input to the power combining means 13 through the 90-degree phase shifting means 14 with respect to the received signal from the one-side short-circuit type microstrip antenna 1a. A phase difference of ° occurs, and circularly polarized waves can be received. In the connection shown in FIG. 1, a right-handed circularly polarized wave mainly from the z-axis direction can be received.

Here, when the antenna element 1 is for GPS reception and the material of the dielectric substrate 2 is a dielectric ceramic, the dimensions of each part of the antenna element 1 with respect to the relative dielectric constant εr are as shown in Table 2 below. Become.

[Table 2] Therefore, although the length W1 of one side of the antenna element 1 of the present invention shown in FIG. 1 is the same as the length W2 of one side of the conventional antenna element 41 shown in FIG. 4, the depth dimension D1 is shown in FIG. Depth dimension D2 of conventional antenna element 41
略 of the length. As a result, the area is reduced to approximately 、, the miniaturization and the rectangular parallelepiped shape are achieved at the same time, and an antenna suitable for incorporating a portable device is realized. In particular, if the antenna element 1 is formed by using the dielectric substrate 2 having a relative dielectric constant εr of about 35 or more, a recent small-sized
An antenna element having a thickness equal to or less than the thickness of the thinned mobile phone can be used, and the design of the mobile phone is not spoiled.

Here, the circularly polarized antenna device 1 shown in FIG.
In the low-noise amplifier 10 of FIG. 10, as compared with the low-noise amplifier 50 of the conventional circularly polarized antenna device 400 shown in FIG. 4, a power combining means 13 and a 90 ° phase shift means 14 are added. It appears that the cost increases due to the increased number of components. However, the power combining means 1
The 3 and 90 ° phase shifting means 14 are both provided on a dielectric substrate (not shown) which actually constitutes the low noise amplifier 10.
Since it can be constituted only by microstrip lines, there is no increase in cost.

The antenna element 1 and the low noise amplifier 10
Is connected to a dielectric substrate (not shown) by connecting the short-circuit portions 4a and 4b of the short-circuit electrode 4 of the antenna element 1.
This is performed by soldering the short-circuit portions 8a and 8b of the short-circuit electrode 8 and the power supply electrodes 5 and 9 to electrodes (not shown) formed on a dielectric substrate constituting the low-noise amplifier 10. As a result, the antenna element 1 and the low-noise amplifier 10 are electrically connected, and both are fixed mechanically, so that the integrated circularly polarized antenna device 100 is realized. In this case, since the antenna element 1 can be handled as a surface-mounted electronic component, in actual production, soldering or the like is performed in the same process as the surface-mounted electronic component constituting the low-noise amplifier 10. Becomes possible.

FIG. 2 is a diagram showing an example of the reception directivity of the circularly polarized antenna device 100 shown in FIG. FIG. 2 shows the relative reception power P normalized by the reception power in the z-axis direction with respect to the reception directivity of the right-handed circularly polarized wave component on the xz plane in the coordinate system of FIG. From FIG. 2, it can be seen that, in the circularly polarized antenna device 100 of the present invention, the right-handed circularly polarized wave is favorably received over a wide angle.

FIG. 3 shows a second embodiment of the circularly polarized antenna device according to the present invention.
Reference numeral 0 denotes a combination of the antenna element 21 and the low noise amplifier 10. A patch electrode 23 and a patch electrode 27 are formed on the upper surface of the substantially rectangular parallelepiped dielectric substrate 22 of the antenna element 21 at positions orthogonal to each other along one axis, that is, the y-axis in FIG. A ground electrode 26 is formed on almost the entire bottom surface of the dielectric substrate 22. The dielectric substrate 22 has through holes 30 and 3.
1 is provided, and the vicinity of the through holes 30 and 31 in the ground electrode 26 formed on the other surface of the dielectric base 22 is
The ground electrodes 26 are removed by the removal units 32 and 33.

The patch electrode 23 and the patch electrode 27 have substantially the same shape. The patch electrode 23 is connected to the ground electrode 26 via the short-circuit electrode 24 on the front side surface in FIG. For power supply, the power supply pin 25 is inserted into the through hole 30 and the power supply pin 2
5 is connected to the patch electrode 23 by soldering or the like. With such a configuration, the one-side short-circuit type microstrip antenna 21a is configured. The position of the through hole 30 and the feed pin 25 is such that the input impedance of the one-side short-circuit type microstrip antenna 21a is, for example, 50.
It is set to be ohm.

On the other hand, the patch electrode 27 is connected to the ground electrode 26 via the short-circuit electrode 28 on the right side of FIG.
The power supply is performed by inserting the power supply pin 29 into the through hole 31 and connecting the power supply pin 29 to the patch electrode 27 by soldering or the like. With such a configuration, the one-side short-circuit type microstrip antenna 21b is configured. Through hole 31
The position of the feed pin 29 is such that the input impedance of the one-side short-circuited microstrip antenna 21b is, for example,
It is set to be 0 ohm.

The low noise amplifier 10 shown in FIG. 3 is the same as the low noise amplifier 10 shown in FIG.

The antenna element 21 shown in FIG. 3 is composed of two one-side short-circuited microstrip antennas 21a and 21b, similarly to the antenna element 1 shown in FIG.
Since the polarization planes are different from each other by 90 ° and the power is electrically combined with a phase difference of 90 °, circularly polarized waves can be received. In the connection of FIG. 3, it is possible to receive mainly right-handed circularly polarized waves mainly from the z-axis direction. The dimensions of each part are substantially the same as those of the first embodiment shown in FIG. 1, and the miniaturization and the rectangular parallelepiped shape of the circularly polarized antenna device 200 including the antenna element 21 are simultaneously achieved. As a result, a suitable antenna is realized.

In the first embodiment shown in FIG. 1, the antenna element 1 is combined with the power combining means 13 and the 90 ° phase shift means 14 in the low noise amplifier 10 to form a circularly polarized antenna device. 100, but the power combining means 13 and 9
3 dB 9 having both functions of the 0 ° phase shift means 14
Even if you replace it with an electronic component called a 0 ° hybrid,
It is possible to configure the circularly polarized antenna device 100 of the present invention. The same applies to the circularly polarized antenna device 200 according to the second embodiment shown in FIG.

In the first embodiment shown in FIG. 1, the antenna element 1 is combined with the power combining means 13 and the 90 ° phase shifting means 14 in the low noise amplifier 10 to form a circularly polarized antenna device. 100, but the polarization is 90 ° by using the feed electrodes 5 and 9 of the antenna element 1 independently.
It is also possible to function as two different antennas, for example, it can be applied as a polarization diversity antenna. The same applies to the antenna element 21 of the second embodiment shown in FIG.

[0031]

In the circularly polarized antenna device according to the present invention, two one-sided short-circuited microstrip antennas are formed on one dielectric substrate so as to be orthogonal to one axis, and a 90 ° phase difference feed (or 90 ° phase difference feed) is performed. (Power combining by phase difference), it is possible to realize a small rectangular parallelepiped circularly polarized antenna device suitable for being built in a portable device or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a circularly polarized antenna device according to the present invention.

FIG. 2 is a diagram illustrating an example of directivity of the circularly polarized antenna device illustrated in FIG. 1;

FIG. 3 is a diagram showing another embodiment of the circularly polarized antenna device according to the present invention.

FIG. 4 is a diagram showing a conventional circularly polarized antenna device.

[Explanation of symbols]

 100, 200 Circularly polarized antenna device 1, 21, Antenna element 2, 22 Dielectric substrate 3, 7, 23, 27 Patch electrode 6, 26 Ground electrode 4, 8, 24, 28 Short-circuit electrode 5, 9 Feed electrode 25, 29 Power supply pin 10 Low noise amplifier 13 Power combining means 14 90 ° phase shifting means

Claims (3)

[Claims] 1. A dielectric substrate having a substantially rectangular parallelepiped shape, two patch electrodes provided in parallel in the longitudinal direction of an upper surface of the dielectric substrate and provided orthogonal to each other, and provided on a lower surface of the dielectric substrate. A ground electrode, a first short-circuit electrode provided on a longitudinal side surface of the dielectric base, and electrically connecting one of the patch electrodes to the ground electrode, and a first short-circuit electrode provided on a lateral side of the dielectric base. A second short-circuit electrode for electrically connecting the other of the patch electrodes to the ground electrode, and a second short-circuit electrode provided on the side of the patch electrode on which the short-circuit electrode is provided, corresponding to each of the patch electrodes; An antenna element comprising: a feed electrode electrically connected to each of the patch electrodes. 2. A dielectric substrate having a substantially rectangular parallelepiped shape, two patch electrodes provided in parallel in the longitudinal direction of an upper surface of the dielectric substrate and provided orthogonal to each other, and provided on a lower surface of the dielectric substrate. A ground electrode, a first short-circuit electrode provided on a longitudinal side surface of the dielectric base, and electrically connecting one of the patch electrodes to the ground electrode, and a first short-circuit electrode provided on a lateral side of the dielectric base. A second short-circuit electrode for electrically connecting the other of the patch electrodes and the ground electrode, and a through-hole of the dielectric substrate formed from each patch electrode toward the ground electrode, An antenna element, comprising: a power supply electrode provided corresponding to each patch electrode and electrically connected to each patch electrode. 3. The 90 ° phase shifting means is electrically connected to one of the feeding electrodes of the feeding electrode of the antenna element according to claim 1 and the other of the 90 ° phase shifting means and the feeding electrode. A circularly polarized antenna device, wherein a power combining means is electrically connected between the power supply electrode and the power supply electrode.