The Antenna Guy

To continue on the topic of the printed quadrifilar antennas, as promised, this post will be about the feeding network. Last post I've shown the antenna part and a quick explanation as to what the feeding network should look like, this time I'm going to cover the power distribution network that makes it all work. More specifically, I'll explore an alternative that allows the antenna construction to be more compact and with better performance. So the idea is to create a system which has one single input port and four output ports, where all the outputs have the same power and 90º sequential phase difference between them, as explained in the last post.  But how exactly does that work and why the antenna becomes circularly polarized, when the single element of the antenna has linear polarization? Well, if you generate two orthogonal electric field components with a 90º phase difference between them, then the ...

Hey there folks!    Today I'm heading back to the RFID reader antennas topic. This time, I'm covering another typical antenna found in these readers, which is the quadrifilar antenna. In this particular case, a printed implementation of the quadrifilar antenna. These antennas are composed of four arms, either monopoles or PIFA type elements, where each of the elements is fed with a 90º phase delay in between in order to create a circularly polarized radiation. Another common place for quadrifilar antennas is the helix type antennas used for VHF and UHF band communications and GNSS applications. These are very popular among HAMs and also some commercial applications. Here's some examples: ...

Hey there folks. Today I'm going to talk about curves in PCB tracks. I've seen a few topics here and there trying to demystify the way that tracks should curve in order to avoid all sorts of magic stuff. There seems to be a large consensus about avoiding 90º degrees bend at all costs, then there's a lot of people already claiming we've been doing stuff based on tradition only and that there's no solid reason nor practical argument to not use 90º bent tracks. So I thought I should give my two cents on this subject. I f you want to indulge in such a discussion, check out this EDA stack overflow thread . The most voted answer of said thread is certainly very detailed and mostly demystifies religious beliefs about the 90 degree angles in the tracks. But I also feel it ends up going overboard with statements such as: "In fact, this is true even at very high frequencies, which I will address further down in this post. If I...