Wireless tag communication device and sheet processing apparatus

A sheet processing apparatus, comprising:

• a sheet conveyance path configured to convey a sheet having a wireless tag;
• and
• a wireless tag communication device configured to communicate with the wireless tag and including:
• an antenna with a plurality of radiation regions from which a polarized radio wave is emitted and including:
• a first radiation region extending along a first direction perpendicular to a conveyance direction of the wireless tag along the conveyance path and having a first length in the first direction,
• a second radiation region extending parallel to the first radiation region along the first direction and having a second length that is different from the first length in the first direction,
• a third radiation region extending along the conveyance direction and having a third length in the conveyance direction, and
• a fourth radiation region extending parallel to the third radiation region along the conveyance direction and having a fourth length that is different from the third length in the conveyance direction, and
• a controller configured to cause at least one of the first, second, third and, fourth radiation regions to emit a polarized wave toward the wireless tag, wherein
• each of the first and second radiation regions partially overlaps both the third radiation region and the fourth radiation region in a direction along which the polarized wave is emitted.

An antenna for a wireless tag communicating device configured to communicate with a wireless tag conveyed by a conveyance mechanism, the antenna comprising:

• a plurality of radiation regions from which a polarized radio wave is emitted, the plurality of radiation regions including:
• a first radiation region extending along a first direction perpendicular to a conveyance direction of the wireless tag and having a first length in the first direction,
• a second radiation region extending parallel to the first radiation region along the first direction and having a second length that is different from the first length in the first direction,
• a third radiation region extending along the conveyance direction and having a third length in the conveyance direction, and
• a fourth radiation region extending parallel to the third radiation region along the conveyance direction and having a fourth length that is different from the third length in the conveyance direction, wherein
• each of the first and second radiation regions partially overlaps both the third radiation region and the fourth radiation region in a direction along which the polarized wave is emitted.