Wireless communication system

A wireless communication system comprising:

• a housing formed of a conductive material and having an inner upper surface, an inner lower surface, and a pair of inner side surfaces;
• a plurality of battery packs installed in the housing, each of the battery packs having outer surfaces formed of a conductive material, the outer surfaces including an outer upper surface;
• a first wireless communication device;
• and
• a second wireless communication device, wherein:
• each of the first and second communication devices mainly includes an antenna disposed in a corresponding one of first and second propagation paths defined between the housing and one or more of the battery packs, the first and second wireless communication devices being configured to perform radio-wave wireless communication with one another using a predetermined communication frequency;
• a first radio-wave cutoff frequency of a vertical polarization plane is defined in the first propagation path;
• a third radio-wave cutoff frequency of a horizontal polarization plane is defined in the first propagation path;
• the first propagation path is defined by the inner upper surface, the inner lower surface, and the pair of inner side surfaces of the housing;
• a distance between the inner upper and lower surfaces of the housing is smaller than that between the pair of inner side surfaces of the housing;
• a second radio-wave cutoff frequency of the vertical polarization plane is defined in the second propagation path;
• a fourth radio-wave cutoff frequency of the horizontal polarization plane is defined in the second propagation path;
• the second propagation path is defined by the inner upper surface of the housing, the outer upper surfaces of the battery packs, and the pair of inner side surfaces of the housing;
• a distance between the inner upper surface of the housing and the outer upper surface of each battery pack is smaller than that between the pair of inner side surfaces of the housing;
• the predetermined communication frequency is set to be higher than the first and third radio-wave cutoff frequencies, higher than the second radio-wave cutoff frequency, and lower than the fourth radio-wave cutoff frequency;
• and
• the antenna of each of the first and second wireless communication devices is configured to transmit and receive radio waves having the vertical polarization plane more strongly than other radio waves having directional polarization planes other than the vertical polarization plane.

A wireless communication system comprising:

• a housing formed of a conductive material and having an inner upper surface, an inner lower surface, and a pair of inner side surfaces;
• a plurality of battery packs installed in the housing, each of the battery packs having outer surfaces formed of a conductive material, the outer surfaces including an outer side surface;
• a first wireless communication device;
• and
• a second wireless communication device, wherein:
• each of the first and second communication devices mainly includes an antenna disposed in a corresponding one of first and second propagation paths defined between the housing and one or more of the battery packs, the first and second wireless communication devices being configured to perform radio-wave wireless communication with one another using a predetermined communication frequency;
• a first radio-wave cutoff frequency of a vertical polarization plane is defined in the first propagation path;
• a third radio-wave cutoff frequency of a horizontal polarization plane is defined in the first propagation path;
• the first propagation path is defined by the inner upper surface, the inner lower surface, and the pair of inner side surfaces of the housing;
• a distance between the inner upper and lower surfaces of the housing is smaller than that between the pair of inner side surfaces of the housing;
• a second radio-wave cutoff frequency of the vertical polarization plane is defined in the second propagation path;
• a fourth radio-wave cutoff frequency of the horizontal polarization plane is defined in the second propagation path;
• the second propagation path is defined by the inner upper surface of the housing, the inner lower surface of the housing, the outer side surfaces of the battery packs, and one of the pair of inner side surfaces of the housing;
• a distance between the inner upper and lower surfaces of the housing is greater than that between the outer side surface of each battery pack and the one of the pair of inner side surfaces of the housing;
• the predetermined communication frequency is set to be higher than the first and third radio-wave cutoff frequencies, lower than the second radio-wave cutoff frequency, and higher than the fourth radio-wave cutoff frequency;
• and
• the antenna of each of the first and second wireless communication devices is configured to transmit and receive radio waves having the horizontal polarization plane more strongly than other radio waves having directional polarization planes other than the horizontal polarization plane.