---
tags:
  - science/physics
  - electromagnetic-radiation
  - radio
  - microwave
  - terahertz
  - sensors
created: 2026-05-16
breadcrumb: "Physics > Electromagnetic radiation > Radio, microwave, THz"
---

# Radio, microwave, THz

> **Mechanism:** Electromagnetic wave reception

## Items

- **Antenna + rectifier** — Antenna captures the field, a diode rectifier demodulates.
- **Crystal diode** — Point-contact diode demodulator. The original cat's-whisker AM radio detector.
- **Microwave bolometer** — Thermal RF detector; absorbed power heats a sensitive resistor.
- **SIS junction** — Superconductor-insulator-superconductor tunnel junction; quantum mixer used in mm-wave radio astronomy (ALMA).
- **HEMT mixer** — High-electron-mobility transistor; low-noise mixing across microwave bands.

## Related

- [[visible-light]]