Tag, interrogator, and system for performing position measurement based on backscatter in millimeter-wave band

An interrogator for performing position measurement based on backscatter in a millimeter-wave band, the interrogator comprising:

• a transceiver;
• and
• at least one processor connected to the transceiver, wherein the at least one processor is configured to:
• output an interrogation signal including continuous unit chirp signals that change from a first frequency to a second frequency;
• receive a backscattered tag signal from a tag that has received the output interrogation signal;
• and
• measure a position of the tag by isolating the tag signal and identifying frequency-shift keying (FSK) modulation applied to the backscattered tag signal,
• wherein the tag comprises a frequency-shift keying (FSK) modulator connected to a planar Van Atta array antenna,
• wherein an incident signal received by an upper antenna may be output from a lower antenna of a centrosymmetric antenna pair in the planar Van Atta array antenna,
• wherein the FSK modulator comprises a 90° hybrid coupler, the 90° hybrid coupler being configured to deliver the interrogation signal through a first path, a second path, a third path, and a fourth path,
• wherein, among the interrogation signal, a first signal delivered through the first path and a second signal delivered through the second path are induced to undergo a 180° phase shift with respect to each other to offset each other, and
• wherein, among the interrogation signal, a third signal delivered through the third path and a fourth signal delivered through the fourth path, having no phase difference therebetween, are summed up to a maximum and output.

A system for performing position measurement based on backscatter in a millimeter-wave band, the system comprising:

• an interrogator configured to output an interrogation signal including continuous unit chirp signals that change from a first frequency to a second frequency;
• and
• a tag configured to receive the interrogation signal, apply frequency-shift keying (FSK) modulation to the interrogation signal, and transmit a tag signal to which the FSK modulation is applied, in a direction from which the interrogation signal is incident,
• wherein the interrogator is further configured to measure a position of the tag by identifying the FSK modulation applied to the tag signal,
• wherein the tag comprises a frequency-shift keying (FSK) modulator connected to a planar Van Atta array antenna,
• wherein an incident signal received by an upper antenna may be output from a lower antenna of a centrosymmetric antenna pair in the planar Van Atta array antenna,
• wherein the FSK modulator comprises a 90° hybrid coupler, the 90° hybrid coupler being configured to deliver the interrogation signal through a first path, a second path, a third path, and a fourth path,
• wherein, among the interrogation signal, a first signal delivered through the first path and a second signal delivered through the second path are induced to undergo a 180° phase shift with respect to each other to offset each other, and
• wherein, among the interrogation signal, a third signal delivered through the third path and a fourth signal delivered through the fourth path, having no phase difference therebetween, are summed up to a maximum and output.