Low-Profile Penta-Band Automotive Patch Antenna Using Horizontal Stacking and Corner Feeding

Connected cars with a multitude of frequency bands to be covered for the 4G and 5G mobile communication standards would benefit immensely from the low-profile and compact multi-band antenna designs. This paper considers the simulation, design, and measurement aspects for an innovative penta-band patch antenna that operates in the LTE-1800 uplink (1.71–1.78 GHz), LTE-1800 downlink (1.805–1.875 GHz), UMTS uplink (1.92–1.998 GHz), UMTS downlink (2.11–2.17 GHz), and LTE-2600 (2.5–2.69 GHz) frequency bands encompassing a total bandwidth of approximately 468 MHz, 261 MHz of which was covered with <inline-formula> <tex-math notation="LaTeX">$|S_{11}|^{2}< -10$ </tex-math></inline-formula> dB and the remaining with <inline-formula> <tex-math notation="LaTeX">$|S_{11}|^{2}< -6$ </tex-math></inline-formula> dB in the measurement. We achieved the multi-band behavior by simultaneous exploitation of the principles of horizontal stacking and corner feeding of the microstrip patch antennas. The maximum value of the measured realized gain, i.e., 5 dBi, was obtained for the LTE-2600 band, while its minimum value, i.e., −1.7 dBi, was obtained for the LTE-1800 downlink band. The measured realized gain was between 2 and 3 dBi at all other frequencies. A thickness of just 1.7 mm makes the antenna very low-profile, which, in addition to its compact dimensions (175 mm <inline-formula> <tex-math notation="LaTeX">$\times \,\, 47$ </tex-math></inline-formula> mm), makes it suitable for embedding/mounting in many promising locations around a car, such as in rooftop cavities, or in exterior plastic paneling.