Radiolähetteisiä

Radiolähetteisiä are a class of compact, low‑power radio‑transmitting devices that use a lattice‑like array of tiny antennas embedded in a flexible substrate. The term originates from the Finnish words “radio” and “lähette,” meaning “plate” or “sheet.” They were first developed in the late 1970s by researchers at the University of Helsinki as part of a project to reduce the bulk of wireless modules in consumer electronics. By arranging miniature dipole elements in a regular grid, the devices can radiate electromagnetic signals efficiently while remaining thin and pliable.

The basic construction comprises a polymer film with silver or copper traces forming the antenna array, covered by a clear epoxy. The lattice spacing is typically 7–10 mm, allowing operation in the 2.4 GHz ISM band with a maximum output power of 5 mW. Because the radiation pattern is isotropic, radiolähetteisiä are particularly suited for applications that require omnidirectional coverage, such as wireless sensor networks, RFID tags, and low‑energy IoT gateways. In medical devices they are used for telemetry in implantable pacemakers and drug‑delivery systems, where minimal size and tissue safety are critical.

Manufacturing radiolähetteisiä involves batch lithography and automated spot‑welding of the power supply to the lattice, making them economical for mass production. Their small size and flexibility have spurred research into wearable health monitors, where wristbands and patches can embed the lattice to transmit patient data to nearby receivers. Safety standards for radiolähetteisiä are regulated by the International Telecommunication Union (ITU) and national telecom authorities, ensuring that the emitted power remains well below exposure limits for the human body.