Monitoring core body temperature (CBT) is vital for health care, sports, and firefighters. Even though invasive sensors give accurate measurement of CBT, due to patient discomfort and optimal sensor placement inside the body, it is mostly used in intensive care and surgical units. Among the non-invasive CBT measurement techniques, ear canal tympanic membrane (TM) temperature measured by infrared (IR) sensor has good correlation with the pulmonary artery as it gets blood supply from the internal carotid artery that supplies blood to the brain. Thermal radiation in IR regime has penetration depth (PD) of few mm and measurement is affected by ear wax. Unlike IR spectrum, thermal radiation in microwave regime (1-4 GHz) has PD of several cm and is less influenced by ear wax. However, it is challenging to design miniaturized microwave antenna for placement at the ear canal. In this research, the feasibility of microwave radiometry (MWR) for CBT measurement will be explored using miniaturized wearable microwave antennas. Design challenges and electromagnetic interference arising due to miniaturization of receive antenna and microwave receiver will be addressed in this research for developing a wearable device for CBT monitoring.