What antennas does a modern car use?
Modern vehicles integrate many antennas: broadcast AM/FM and digital radio (often printed on rear glass), GNSS, cellular and V2X in roof “shark-fin” modules, Wi-Fi and Bluetooth inside the cabin, keyless entry and tire-pressure sensors at sub-GHz, UWB anchors for digital keys, and 76–81 GHz radar arrays behind bumpers.[1][2]
Why are shark-fin modules used?
They combine short monopoles and patches for cellular, GNSS and satellite radio in an aerodynamic radome on the metal roof, which acts as a large ground plane. Height limits make low-band cellular difficult and require careful design of loaded monopoles and multiple antennas for MIMO.[3]
How do automotive radar antennas work?
76–81 GHz radars use arrays of printed patches or slot and waveguide antennas with several transmit and receive channels; MIMO radar processing creates a larger virtual array for angular resolution. In the US, 76–81 GHz vehicle radar is governed by 47 CFR 15.253.[1][4] Bumper fascia and paint act as radomes and must be designed for low loss and reflection.
What special challenges exist?
Wide temperature range, vibration, the car body’s effect on patterns, coexistence among many radios, and validation of whole-vehicle performance in large chambers.[2]
Frequently asked questions
Why are FM antennas on the rear window?
Printed conductors on glass are inexpensive, unobtrusive and use the window aperture.
What is V2X?
Vehicle-to-everything communication, using cellular sidelink or IEEE 802.11p-based systems near 5.9 GHz.
Does paint affect radar?
Metallic paints over a radar can attenuate and reflect strongly.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “47 CFR 15.253 — Operation within the band 76-81 GHz”. U.S. FCC, eCFR. current text.
- “Antennas and Propagation for Wireless Communication Systems, 2nd ed.”. S. R. Saunders and A. Aragón-Zavala, Wiley. 2007.
- “Modern Small Antennas”. K. Fujimoto and H. Morishita, Cambridge University Press. 2013.
- “Introduction to Radar Systems, 3rd ed.”. M. I. Skolnik, McGraw-Hill. 2001.