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EP-4290683-B1 - ANTENNA DEVICE AND COMMUNICATION DEVICE

EP4290683B1EP 4290683 B1EP4290683 B1EP 4290683B1EP-4290683-B1

Inventors

  • HAMABE, TAICHI

Dates

Publication Date
20260506
Application Date
20230302

Claims (5)

  1. An antenna device (100) comprising: a feed antenna (104) connected to a feed point (103) and extending from the feed point (103), the feed antenna (104) corresponding to a first frequency; a loop antenna (105) connected to a ground (102) and arranged to surround the feed antenna (104), the loop antenna (105) corresponding to a second frequency lower than the first frequency; and a resonator (115) arranged outside the loop antenna (105) in a direction in which the feed antenna (104) extends, the resonator (115) corresponding to the second frequency, wherein the loop antenna (105) includes an extending portion (110, 111) that extends to protrude outward on a side where the resonator (115) is arranged with respect to the feed point (103), characterized in that the extending portion (110, 111) extends parallel to a longitudinal direction of the resonator (115).
  2. The antenna device (100) according to claim 1, wherein the extending portion (110, 111) includes two extending portions (110, 111), and the two extending portions (110, 111) are arranged to extend on a straight line.
  3. The antenna device (100) according to claim 1, wherein an element length (L1) of the feed antenna (104) is 1/4 of a wavelength of the first frequency, an element length of the loop antenna (105) is a wavelength of the second frequency, and an element length (L4) of a portion (109, 110, 111) parallel to the resonator (115) is 1/2 of the wavelength of the second frequency, the portion (109, 110, 111) including the extending portion (110, 111) and a part (109) of the loop antenna (105).
  4. The antenna device (100) according to claim 1, wherein the first frequency is in a 5 GHz band, and the second frequency is in a 2 GHz band.
  5. A communication device comprising: the antenna device (100) according to any one of claims 1 to 4.

Description

TECHNICAL FIELD The present disclosure relates to an antenna device and a communication device. BACKGROUND ART WO 2021/213125 A1 provides an antenna unit and an electronic device. By means of two feed sources, a signal of a C-mode port and a signal of a D-mode port of the same annular antenna in any antenna unit are respectively excited, and on the basis of the electric symmetrical arrangement of the antenna unit, the signal of the C-mode port self-cancels at the D-mode port, and the signal of the D-mode port self-cancels at the C-mode port, so that signal isolation and interference is achieved between the two ports to self-cancel; in addition, the signal of the C-mode port and the signal of the D-mode port can complement each other in different radiation directions, thereby, on the basis of the same annular antenna, implementing two antennas that have high isolation degrees and that have low envelope correlation coefficients (ECCs). In the paper "A Small Antenna Consisting of Short-Ended Parallel Stubs and Capacitors" by K. Sakaguchi et al. (Electronics & Communications in Japan, Part I - Communications; Wiley, Hobeken, NK., US, vol. 80, no. 4, 1 April 1997, pages 83-95) a small antenna for mobile communication is proposed in which the ends of the shorted parallel plates are folded inward to generate a capacitive load between the gap. The balanced feed happens at an appropriate position on the parallel plates. When dual parallel plates are used, the antenna can be used at dual frequencies. This antenna is considered to be a kind of small loop antenna and can be used at the electric field null (or the peak of the magnetic field) generated near the metallic furniture, a column with internal conductors and walls. In the paper, the far-field radiation pattern and the input impedance of this antenna are computed and the results are compared with the measured results. This comparison demonstrates that the method cannot quantitatively evaluate the antenna characteristics but can be useful for finding the tendency of these characteristics. Next, the design guideline of the antenna is presented according to the analysis method. Miniaturization limitations of the present antenna are discussed. The antenna proposed in the paper has a measured gain of G = -0.3 dBi and a bandwidth of 5.6 percent for a return loss of less than -10 dB with a maximum dimension of one-half wavelength. In order to provide a circularly polarized wave antenna which has good attachment properties, is easy to feed, and has good antenna characteristics, it is proposed in JP 4 976 511 B2 that the circularly polarized wave antenna includes a hot terminal, a ground terminal, a first element, a second element, and a loop element. The first element extends from a hot terminal. The second element extends from the ground terminal to a vertical direction to the first element. The loop element extends from the ground terminal, surrounds the hot terminal, the first element, and the second element, and returns to the ground terminal. In the related art, it is required to extend a frequency that an antenna can apply to a frequency in a wider band. For example, in Wi-Fi 6 among Wi-Fi (registered trademark) which is a wireless communication technology in the related art, an antenna applicable to a 2400 MHz band and a 5000 MHz band is known. JP2005-020289A discloses a configuration in which a loop antenna corresponding to a plurality of frequency bands is provided in one antenna to allow resonance, and the size of the entire antenna device is reduced. SUMMARY OF INVENTION The present disclosure has been devised in view of the above circumstances in the related art, and an object thereof is to provide an antenna device capable of corresponding to a plurality of frequency bands and reducing the size. According to an illustrative aspect of the present disclosure, an antenna device as defined in claim 1 is provided. According to another illustrative aspect of the present disclosure, a communication device includes the antenna device according to the above aspect. Any combination of the above components or a conversion on the expression of the present disclosure between devices, systems, or the like is also effective as an aspect of the present disclosure. According to the present disclosure, it is possible to provide an antenna device capable of corresponding to a plurality of frequency bands and reducing the size. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a diagram showing a configuration example of an antenna device according to a first embodiment;Fig. 2A is a diagram for describing a resonance state of the antenna device according to the first embodiment;Fig. 2B is a diagram for describing a resonance state of the antenna device according to the first embodiment;Fig. 3A is a graph showing VSWR characteristics of the antenna device according to the first embodiment; andFig. 3B is a graph showing VSWR characteristics of the antenna device according to the first emb