To most individuals antenna design and principle is far of a black artwork. Nevertheless, with slightly little bit of eagerness and prepared to be taught anybody can construct their very own antenna design with good outcomes. That is finest demonstrated by Pepijn de Vos’ journey on designing and prototyping a printed PCB antenna for GPS frequencies.

The motivation for the challenge got here after talking with a number of colleagues at an MCH meetup whom labored with maps functions. MCH (Could Include Hackers) is a gathering that takes place in Amsterdam and is organized by volunteers. Its sole objective is to convey like minded people collectively to share data, technical developments, experiments, hacks, and most significantly join with different people with related pursuits. Like many different technical meetups, badges have been distributed to encourage studying and hacking.

The aim of this challenge was so as to add GPS capabilities to the badge. Moreover, the true problem and check was designing and prototyping a customized antenna for GPS frequencies. To start, some background analysis was finished which included reviewing patch antenna design and principle info from the next textbooks: Antenna Concept: Evaluation and Design, Microstrip Antenna Design Handbook, and Circularly Polarized Antennas. Utilizing info discovered from these texts, the size for an oblong path antenna have been calculated for the L1 GPS frequency of 1574MHz. A brief Python script was put collectively for the computations, which is proven under.

As soon as dimensions have been decided, the following steps entailed calculating the 50 Ohm hint width wanted for the precise PCB dielectric and figuring out how one can make the antenna circularly polarized. It seems designing a circularly polarized patch antenna just isn’t precisely straight ahead. Nevertheless, it may be achieved by truncating the corners of the oblong patch. With a very good place to begin decided for the antenna, the following steps concerned a lot of simulation. At first OpenEMS was used since it’s open supply and free. However after yielding odd outcomes that didn’t make a lot sense, it was decided a distinct route would have to be taken. Having seen a whole lot of simulation work accomplished utilizing Sonnet software program elsewhere and figuring out free trial licenses can be found, the remainder of the simulation and design work was accomplished utilizing Sonnet.

Working with Sonnet for the primary time got here with its personal studying curve, although with the assistance of their help workers an optimum antenna design was converged upon in a short while. This was primarily finished by working parametric sweeps on totally different geometries of the patch antenna. Naturally, the following step is to start to convey the antenna to life. Utilizing KiCAD a format was created with the specified dimensions. The truncated patch antenna, an oblong patch antenna, and a microstrip for calibration have been all exported into Gerber information. These have been then dropped at the native hackerspace, Tkkrlab, to mill out a two sided PCB utilizing a CNC machine.

The ultimate steps included the thrilling a part of testing the design. First, the return loss or S11 was measured utilizing a LiteVNA. This confirmed a S11 response that carefully matched the simulated outcomes. Subsequent, the u-blox MAX-M10S GNSS module was acquired. This low energy, asset monitoring machine will finally be what permits GPS on the badge. After tinkering with the I2C interface, the antenna and module mixture have been linked to the badge and NMEA messages started showing on the show. The antenna was working, receiving satellite tv for pc communications, and the situation was discovered! Total, the method of antenna design and prototyping yielded a profitable PCB patch antenna for GPS frequencies.