Patch antennas operating at two frequencies without a substrate
What is it about?
Patch antennas are a type of printed circuit antenna - typically rectangular or square, but also often circular, or triangular. The patch can be modified to allow it to work at more than one frequency, such as by placing slots (regions of no metal) within the patch. The printed circuit board ("substrate") introduces losses that are of increasing significance at higher frequencies, where power generation is limited and atmospheric absorption increases. This paper looks at the use of "air-spaced" patch antennas (so, no substrate but air) and the use of two methods for introducing dual frequency operation. The air substrate means the patch must be supported with thin metal strips, which modify the effect of conventional methods for achieving multiple frequency operation.
Why is it important?
When this was published, it was a prototype for millimetre-wave antennas at 60-80 GHz, suitable for dual function automotive radar and telematics antennas. Technology has progressed to the point that the challenges explored here are now being faced at frequencies 300 GHz and above, but the solution explored is still relevant.
The following have contributed to this page: Dr Robert N Foster