971438Phase 2 Prototype Development of a GNSS Antenna Using a Meandered Spiral and High Impedance SurfaceClosedSmall Business Research InitiativeInnovate UKThe Arralis design is a low space, weight and power, wearable (e.g. in a MTP helmet cover for an MK6 helmet) or mountable, spiral antenna which uses a High Impedance Surface (HIS) to reduce the thickness (to < 8 mm). By using a meandered spiral type antenna on a HIS, the surface area is kept within 96 mm x 86 mm, and by incorporating a ground plane, the mounting, or 'contact' interactions are removed, meaning that the antenna can be positioned easily on equipment or clothing. The work from Phase 1 shows that the single connection component is well matched to 50 ohms from GPS L5 to GPS L1 frequency bands using a stripline Marchand Balun, and operates using Right-Hand Circularly Polarised (RHCP) waves with an in-band axial ratio < 3 dB. By using a multi-resonant HIS to introduce multiple in-band, in-phase waves from the antenna reflector, the antenna gain and radiation efficiency are increased over a wider bandwidth than conventional antennas and with the added advantage that the thickness and weight are kept to a minimum. This highly repeatable design will be manufactured using existing PCB manufacturing processes to ensure high yields on a technology that is resilient for battlefield conditions, and to keep the costs to a minimum. Furthermore, flexible or woven materials will be implemented to render the device suitable for on-body applications. Simulation results performed in Phase 1 show good performance with the antenna having passive gain in all bands at the larger antenna size. Simulations also show that the antenna can operate, with low dc consumption using active gain, at a lower size and profile.