The NCAR Phased Array Radar Line Replacement Unit (LRU): Integration, Characterization and Performance

A small prototype line replacement unit (LRU) has been developed as a proof of concept and technology demonstrator for phased array radar in NCAR’s Earth Observing Laboratory. This dual-polarized, and 2-D scanning array prototype concept first formed in 2013 (Salazar et al. 2013) with a tile configuration and transitioned into a commercial-of-the-shelf (COTS) brick configuration to reduce cost and development time. The preliminary design has gone through a couple iterations of improvement in Transmit/Receive Module (TRM).

In the Transmit/Receive Module design, we have achieved the targeted performance in terms of receiver noise figure, RF output power, and power efficiency. A noise figure of 3.3 dB has been achieved, which provides very good receiver sensitivity. The RF beamformer works well and achieves the desired resolution. In new PCB design, we used single via-hole stitch alongside transmission line that improves channel-to-channel isolation. We also simulated a via-hole and transmission line to verify our design. Most simulated results are very close to the measured data.

Two of the TRMs were fabricated with total of two rows, 16 individual TRMs. The latest TRMs will be integrated with the existing radiating aperture (Salazar et al. 2013) for an end-to-end characterization. A suite of LabVIEW controls, instruments, along with a compact near-field range scanner, was developed to test and verify preliminary characteristics of the LRU without the use of a full-sized anechoic chamber. This test suite will provide the capability to characterize the LRU.

This paper will describe the latest LRU configuration, its integration and demonstrate the characteristics of the 2x8 array performance.