Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
2001-03-29
2002-05-21
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Microstrip
C343S702000
Reexamination Certificate
active
06392602
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circularly polarized wave antenna for transmitting—receiving a circularly polarized radio wave, and a communication device using the same.
2. Description of the Related Art
FIG. 6A
is a schematic perspective view of a circularly polarized wave antenna contained in a radio wave device.
FIG. 6B
is a cross sectional view of a part taken along line a—a in FIG.
6
A. The circularly polarized wave antenna
30
shown in
FIGS. 6A and 6B
is a circularly polarized wave micro-strip antenna described in Japanese Examined Patent Application Publication No. 7-46762. With the circularly polarized wave antenna
30
, transmission—reception of radio waves in plural different frequency bands is realized. The circularly polarized wave antenna
30
can correspond to plural different systems such as GPS (Global Positioning System) and S-DAB (DAB(Digital Audio Broadcast) using an S band), and so forth.
The circularly polarized wave antenna
30
has the double structure in which MSA (micro-strip antenna)
32
for exciting a fundamental mode (principal mode) is loaded on the upper face of MSA
31
for exciting a higher mode, as shown in
FIGS. 6A and 6B
, in close contact with and coaxially with the MSA
32
.
The higher mode excitation MSA
31
has the configuration in which a circular radiation electrode
34
is formed on the surface of a rectangular parallelepiped dielectric substrate
33
. Feed pins (probes for a higher mode) G
1
, G
1
′, G
2
, and G
2
′ for feeding power to the radiation electrode
34
are inserted into the dielectric substrate
33
. The fundamental mode of excitation of MSA
32
comprises a circular radiation electrode
38
formed on the upper face of the columnar dielectric substrate
37
. Feed pins (fundamental mode probes) F
1
and F
2
for feeding power to the radiation electrode
38
are inserted so as to extend through the substrate.
By externally supplying power to the feed pins F
1
and F
2
, the radiation electrode
38
is excited, so that transmission-reception of a circularly polarized radio wave in the fundamental mode can be carried out. When powers are externally supplied to the feed pins G
1
, G
1
′, G
2
, and G
2
′, respectively, in such a manner that powers in phase with each other are supplied to the feed pins G
1
and G
1
′, and the feed pins G
2
and G
2
′, and powers with a 90° phase shift are supplied to the feed pins G
1
and G
2
, the radiation electrode
34
is excited, and thus, transmission-reception of the circularly polarized radio wave in the higher mode can be carried out.
In this patent specification, the fundamental mode is defined as a mode having the lowest resonance frequency in plural set excitation (resonance) modes, and the higher mode is defined as a mode having a resonance frequency higher than the lowest resonance frequency. Reference numeral
40
in
FIGS. 6A and 6B
designates a center pin for compensating for the symmetry of the fundamental and higher modes.
With the circularly polarized wave antenna
30
configured as described above, transmission—reception of radio waves in plural different frequency bands can be carried out. On the other hand, there arise the problems that the size of the antenna is increased, since the dielectric substrate
37
is overlaid on the dielectric substrate
33
so as to form plural steps. Furthermore, the circularly polarized wave antenna
30
has a configuration in which power is directed to the radiation electrode by use of the feed pins. With this configuration, problematically, the structure of the antenna
30
becomes complicated. Furthermore, problematically, it is difficult to adjust and set the interval between the respective resonance frequencies in the fundamental and higher modes.
Furthermore, the circularly polarized wave antenna
30
has the following problems. The circuit substrate onto which the circularly polarized wave antenna
30
is mounted is provided with a circuit for driving the circularly polarized wave antenna
30
. In some cases, for the purpose of reducing size, the circuit is formed on the back face opposite to the surface having the antenna mounted thereto. In the circularly polarized wave antenna
30
, the feed pins are disposed near to the center of the dielectric substrate
31
. Accordingly, in the case of the circuit provided on the back face of the circuit substrate as described above, it is difficult to electrically connect the feed pins and the circuit to each other sufficiently, and moreover, there is the problem that patterning the circuit is difficult.
SUMMARY OF THE INVENTION
To solve the above problems, the present invention has been devised. It is an object of the present invention to provide a circularly polarized wave antenna which realizes transmission—reception of circularly polarized radio waves in both fundamental and higher modes, and is small in size, and with which a good circularly polarized wave characteristic can be easily obtained, and to provide a communication device using the same. It is another object of the present invention to provide a circularly polarized wave antenna in which the interval between the respective resonance frequencies in the fundamental and higher modes can be easily adjusted and set, and a communication device using the same.
To achieve the above and other objects, according to the present invention, there is provided a circularly polarized wave antenna which comprises a substantially circular dielectric substrate, a radiation electrode for transmitting—receiving a circularly polarized radio wave formed on the upper face of the dielectric substrate, a fundamental mode feed electrode for feeding power to the radiation electrode to excite the radiation electrode in a fundamental mode, and a higher mode feed electrode for feeding power to the radiation electrode to excite the radiation electrode in a higher mode, the fundamental and higher mode feed electrodes being formed on the side peripheral face of the dielectric substrate and being configured so as to feed the powers to the radiation electrode via capacitive coupling.
Preferably, the radiation electrode is substantially circular, and is provided on the upper face of the dielectric substrate with the center of the radiation electrode being positioned substantially on the center axis of the dielectric substrate. Also preferably, the radiation electrode has such a form as to carry out degeneracy-separation.
Preferably, the radiation electrode is substantially a ring-shape, and is provided on the upper face of the dielectric substrate with the center of the ring of the radiation electrode being positioned substantially on the center axis of the dielectric substrate, and the non-electrode portion enclosed by the ring-shaped radiation electrode comprises a frequency setting portion for adjusting and setting the interval between the respective resonance frequencies in the fundamental and higher modes.
More preferably, a concavity or through-hole is formed in the non-electrode portion enclosed by the substantially ring-shaped radiation electrode in the dielectric substrate.
According to the present invention, there is provided a communication device which includes the circularly polarized wave antenna described above.
According to the present invention having the above-described constitution, when power is supplied from the fundamental mode feed electrode formed on the side peripheral face of the substantially columnar dielectric substrate to the radiation electrode formed on the upper face of the dielectric substrate via capacitive coupling, the radiation electrode is excited in the fundamental mode, so that transmission—reception of a circularly polarized radio wave in the fundamental mode can be carried out. Moreover, when power is supplied from the higher mode feed electrode to the radiation electrode via capacitive coupling, the radiation electrode is excited in the higher mode, so that transmission—reception of the circularly polarized radio wave
Akiyama Hisahi
Ito Shigekazu
Kawahata Kazunari
Yuasa Atsuyuki
Clinger James
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Wong Don
LandOfFree
Circularly polarized wave antenna and device using the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circularly polarized wave antenna and device using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circularly polarized wave antenna and device using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2821542