Microstrip colinear antenna array for a lobe differencing correlation radiometer (LDCR)

We present a lobe-differencing antenna designed as a 2×2 rectangular L-band microstrip antenna array that is used for the CU/BlackSwift Technology's Lobe Differencing Correlation Radiometer (LDCR). The antenna array will be integrated into the fuselage of the BST Tempest unmanned aerial system (UAS). A prototype 2×1 microstrip colinear (“MiCo”) antenna array operating at 1.4135GHz, which is the desired system working frequency, was measured to validate the accuracy of HFSS simulation results of input impedance and radiation pattern. Further, a 2×2 MiCo antenna array was investigated by studying how separation of the upper and lower array pairs and orientation impact mutual coupling, resonant frequency, and radiometer sensitivity. Effective use of styrofoam blocks for improving the antenna's mechanical stability and tuning its resonant frequency was studied. An optimal vertical separation distance was identified that minimizes mutual coupling and provides maximum main to back lobe ratio. A method for tuning the antenna resonant frequency was also developed.