FIG. 5B is a block diagram illustrating components of an example dual-mode localization device 520 configured to operate as an interrogator or as a transponder. Dual-mode localization device 520 comprises a substrate 522 having four antennas disposed thereon. These antennas include interrogator transmit antenna 524, interrogator receive antenna 526, target device transmit antenna 528, and target device receive antenna 530. The localization device 520 further comprises a semiconductor die 532 mounted on substrate 522. The semiconductor die 532 has interrogator circuitry 534 and target device circuitry 536 integrated thereon.
As shown in FIG. 5B, interrogator transmit antenna 524 is differentially coupled to interrogator circuitry 534 via transmission lines 525a and 525b, and interrogator receive antenna is differentially coupled to interrogator circuitry 534 via transmission lines 527a and 527b. Target device transmit antenna 528 is differentially coupled to target device circuitry 536 via transmission lines 529a and 529b. Target device receive antenna 530 is differentially coupled to target device circuitry 536 via transmission lines 531a and 531b. Though in the illustrative embodiment of FIG. 5B each of the antennas 524, 526, 528, and 530 is differentially coupled to circuitry on the semiconductor die 532, in other embodiments one or more of these antennas may not be differentially coupled to the circuitry.
