3D Printed Helix Antenna for 77GHz

In this work, an additively manufactured helix antenna for a center frequency of $\mathrm{f}_{c}\,=77$ GHz is presented. A novel feed concept is proposed including a transition from the helix coil to an E-band waveguide, which allows for tuning of antenna matching. Measurements suggest a -15dB-bandwidth of $\mathrm{B}_{15dB}=8$ GHz and -10dB-bandwidth of $\mathrm{B}_{10dB}=16$ GHz respectively with a fractional -10dB-bandwidth of 20%. An axial ratio below AR $\lt 5$ dB is achieved within the entire $\mathrm{B}_{-10dB}$ and even AR $\lt 3$ dB within $\mathrm{B}_{-15dB}$ in main lobe direction. The realized antenna gain ranges at $\mathrm{G}_{LP}\approx 11$ dBi in linear polarization component yielding a circular polarization gain of $\mathrm{G}_{CP}\approx 12$ to 13dBi. Hence, measurements suggest general feasibility of the proposed helix antenna for mmWave applications despite the relatively high structure complexity due to the miniaturized dimensions at the aimed frequencies.