Enhanced terahertz radiation directivity via a conical horn antenna from on-chip spintronic emitters

A circular waveguide-fed conical horn antenna is fabricated using two-photon lithography (TPL) and integrated with a spintronic terahertz radiation emitter source to provide enhanced radiation directivity. In comparison to the bare terahertz radiation source, incorporating the antenna permits a spectral density gain up to 20.5 dB. The antenna has a smaller footprint and operates at higher frequencies than other reported conical horns, thereby demonstrating the potential of two-photon lithography for the fabrication of terahertz structures for on-chip applications. The use of two-photon lithography for the fabrication of terahertz antennas is anticipated to support the development of technologies operating above 1 THz for broadband, next-generation wireless free-space communications.