# NC State demonstrates a laser-induced plasma filament antenna transmitting 30 MHz radio waves in the lab

- Published: 2026-11-05 18:12 UTC
- Section: Digital & Computing › Connectivity & internet
- Tags: laser plasma antenna, plasma filament antenna, 30 MHz transmission, contactless antenna feed, capacitive feed, NC State research, IEEE Journal of Microwaves, beam steering antenna, space antennas
- URL: https://realtech.media/news/rt-6518e644231760efa6cba14d_nc_state_demonstrates/

**Researchers at North Carolina State University made a plasma filament in air with a laser and used it to transmit a 30 MHz signal. It is a laboratory demonstration at a distance of about 5 cm.**

![NC State demonstrates a laser-induced plasma filament antenna transmitting 30 MHz radio waves in the lab](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/718b32e7db5c6d71.jpg)
*news.ncsu.edu*

Researchers at North Carolina State University have demonstrated a technique that uses a laser to produce a plasma beam antenna capable of transmitting radio waves, according to news.ncsu.edu. The work is published open access in the IEEE Journal of Microwaves under the title "Laser-Induced-Plasma-Filament Antenna Transmitting 30 MHz VHF" [1]. Authors say it is the first demonstration of this concept [1].

The study was led by Ph.D. student Prya Darshni together with Paul Franzon. Arthur Dogariu of Texas A&M University and Princeton University helped with measurements [1].

## How the plasma antenna works

A laser beam of a specific power and diameter ionizes a thin beam of air and creates a defined shaft of plasma, called a plasma filament [1]. According to the authors, electrons on the edge of the filament behave like the skin electrons of a conductor, so the filament has the basic elements needed to act as an antenna [1].

A direct metallic contact would distort the filament, so the team built a contactless feed. It is a metal ring that acts as a capacitor; the laser passes through the ring, and the plasma filament is surrounded by it [1]. A radio-frequency generator feeds a signal into the capacitor, which creates an electromagnetic field, and the field makes the filament transmit radio waves at the required frequency [1].

The authors state that the laser parameters set the properties of the filament, including its length. Length matters because it determines the frequencies an antenna can transmit and receive [1]. The angle of the antenna can be changed by shifting the direction of the laser, that is, by beam steering [1].

## Measurement results

In the experiment, a 30 MHz signal was fed into the filament through the capacitive feed [1]. The transmitting filament and the receiving antenna were linearly polarized with the same orientation and placed about 5 cm apart, within the unobstructed near field [1]. The received signal strength was first recorded with the capacitive feed alone, with the laser blocked, and then with the filament present [1]. With the filament as the antenna, the signal strength increased 2.5 times (150%) [1].

The team has not demonstrated reception of radio signals by the plasma antenna, though Darshni says there is no reason to believe it would not work as a receiver [1]. The paper also examines the feasibility of such antennas for HF/VHF applications on small to large satellites and aircraft. Franzon notes that in low Earth orbit there is enough air to form a plasma [1]. According to Darshni, the next step is to improve the antenna's performance [1].

## Sources

1. [news.ncsu.edu](https://news.ncsu.edu/2026/10/plasma-beam-antenna/)
2. [Interesting Engineering](https://interestingengineering.com/innovation/worlds-first-laser-plasma-antenna)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-6518e644231760efa6cba14d_nc_state_demonstrates/