A compact and broadband uniplanar Microstrip Antenna (MSA) is proposed for endfire radiation at sub-6 GHz 5G frequency band. The proposed antenna consists of a semi-elliptical radiating element and a U-shaped ground plane. The use of semi-elliptical radiating element results in a wide impedance bandwidth (BW) and compact size. The U-shaped ground plane further improves the bandwidth due to the increased coupling from radiating element to ground. An endfire radiation, 3.8 dBi peak gain, and 49.8% BW are achieved while a compact size of 0.47λ 0 × 0.13λ 0 × 0.008λ 0 (where λ 0 is the wavelength in free space at the center frequency) is kept. To validate the simulation results, prototype of the proposed antenna was fabricated and tested. The measured results are in good agreement with the simulated ones.