Patent ID: 11862858
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A polarization direction measuring device for measuring a polarization direction of a linearly polarized received wave using a plurality of circularly polarized antennas, an arrival direction of the received wave being defined by an AZ angle and an EL angle, the measuring device comprising:
an intensity ratio providing unit configured to provide to the plurality of circularly polarized antennas intensity ratios different depending on an arrival direction for the received wave to be received at the plurality of circularly polarized antennas;
a storage unit storing:
a first intensity ratio table having a plurality of first cells, each of the first cells being identified by an AZ angle and an EL angle, a first intensity ratio of a vertically polarized component of the received wave between two of the circularly polarized antennas is set in each of the first cells associated with the arrival direction of the received wave; and
a second intensity ratio table having a plurality of second cells, each of the second cells being identified by an AZ angle and an EL angle, a second intensity ratio of a horizontally polarized component of the received wave between the two of the circularly polarized antennas is set in each of the second cells associated with the arrival direction of the received wave;

a detector configured to acquire a third intensity ratio of the received wave between the two of the circularly polarized antennas;
an acquiring unit configured to acquire the arrival direction of the received wave; and
an arithmetic unit configured to:
acquire the first intensity ratio of the vertically polarized component of the received wave from the first intensity ratio table corresponding to the acquired arrival direction of the received wave,
acquire the second intensity ratio of the horizontally polarized component of the received wave from the second intensity ratio table corresponding to the acquired arrival direction of the received wave, and
calculate the polarization direction of the received wave as a ratio of the horizontally polarized component and a ratio of the vertically polarized component, the ratio of the horizontally polarized component being determined with an expression (1) and the ratio of the vertically polarized component being determined with an expression (2):

PH=(M−TV)/(TH−TV)  (1)

PV=1−PH  (2)

wherein: PH is the ratio of the horizontally polarized component,
M is the third intensity ratio,
TV is the first intensity ratio,
TH is the second intensity ratio,
PV is the ratio of the vertically polarized component, and

wherein provision of different intensity ratios according to the arrival direction of the received wave by the intensity ratio providing unit is enabled by at least one of:
the intensity ratio providing unit having a non-uniform shape in three-dimensional space;
the intensity ratio providing unit having a non-uniform structure in three-dimensional space;
the intensity ratio providing unit having a material that changes an electrical characteristic of the received wave; and
elements of the circularly polarized antennas having gains which are spatially non-uniform.