Planar Antenna
Understanding Planar Antennas
Planar antennas have revolutionized modern wireless systems by enabling low-cost, mass-producible antennas that integrate directly with RF electronics. Their flat form factor fits into smartphones, laptops, vehicles, and flat-panel satellite terminals.
Planar Antenna Types
- Microstrip patch: Most common. 5-8 dBi gain. Easy to array. Linear or circular pol.
- Slot antenna: Complementary to patch. Bidirectional radiation. Good for integration with SIW.
- Printed dipole: Balanced structure on PCB. Good for Wi-Fi and cellular MIMO.
- Vivaldi: Tapered slot. Ultra-wideband (10:1 bandwidth). Used for radar and imaging.
- Spiral: Frequency-independent. Circularly polarized. Used for direction-finding and EW.
Advantages
- Low profile (thin, conformal).
- Low cost (PCB fabrication).
- Easy to array (integrate with feed network).
- Can be made on flexible substrates (wearable, conformal).
Frequently Asked Questions
What is a planar antenna?
A planar antenna is any flat antenna on a substrate: patches, slots, printed dipoles, Vivaldi, spiral. They are low-profile, low-cost, and mass-producible via PCB fabrication. Dominant for consumer electronics, 5G, automotive radar, and satellite.
How do planar antennas compare to 3D antennas?
Planar antennas offer lower profile, easier manufacturing, and easier arraying. 3D antennas (horns, helical, parabolic reflectors) generally have higher gain, better efficiency, and wider bandwidth. Planar antennas trade some performance for form factor and cost.
What is the typical gain of a planar antenna?
Single patch: 5-8 dBi. Printed dipole: 2-5 dBi. Slot: 5-7 dBi. Vivaldi: 5-12 dBi. Spiral: 5-9 dBi. Higher gain is achieved by arraying multiple elements.