Interferometric Synthetic Aperture Radar (IFSAR or InSAR) uses multiple antenna phase centers to ultimately measure
target scene elevation. Its ability to do so depends on the antenna configuration, and how the multiple phase centers are
employed. We examine several different dual-phase-center antenna configurations and modalities, including a
conventional arrangement where a dedicated antenna is used to transmit and receive with another to receive only, a
configuration where transmit and receive operations are ping-ponged between phase centers, a monopulse configuration,
and an orthogonal waveform configuration. Our figure of merit is the RMS height noise in the elevation estimation.
We show that a monopulse configuration is equivalent to the ping-pong scheme, and both offer an advantage over the
conventional arrangement. The orthogonal waveform offers the best potential performance, if sufficient isolation can be