Indy R1000 Datasheet - Impinj

Indy R1000 ® Electrical, Mechanical, & Thermal Specification
5.4 Antenna Configuration Scenarios
There are two different use scenarios for the Indy R1000 reader chip based on the antenna subsystem. The first one involves a single antenna
configuration as shown in Figure 9. In this application, a circulator is used to isolate the transmit and receive paths. Although the figure illustrates the
more general case where two (or more) physically separated antennas are controlled by a switch, each antenna performs the RX and TX function.
The antenna reflection of CW transmit power in receive mode dominates the receiver compression point requirement. With a maximum transmit
power at the antenna port of +30 dBm and assuming an antenna reflection loss of 15 dB, an in-band blocker of +15 dBm must be tolerated at the
receiver input. In this configuration, an external pad is connected at the Rx_in port to avoid compression of the LNA. A high impedance tap at the
output of the PA is implemented to generate the LO_in signal used to drive the RX mixers.
Tx / Rx _ 2
Tx / Rx _ 1
Band select
Filter
Figure 9: Single Antenna Scenario
Rx _ in
PA _ out
LO _ in
A second scenario allows separate antenna connections for receive and transmit as shown in Figure 10. The figure illustrates the more general case
where two (or more) physically separated antennas are controlled by a switch, with each antenna only performing the RX or TX function. The
isolation between the receive and transmit antennas is 25–30 dB; therefore, the in-band blocker caused by the CW transmit signal is in the order of
+0 dBm. This scenario significantly reduces the compression requirements on the receiver and allows for a more sensitive receiver. A high
impedance tap at the output of the PA is implemented to generate the LO_in signal used to drive the RX mixers.
Figure 10: Dual Antenna Scenario
22 Revision 2.3, Copyright © 2012, Impinj, Inc.