If you’ve ever wondered how dozens of cell phones can scream at the same 5G cell tower at exactly the same time without drowning each other out, the answer lies hidden in the mathematics of pseudo-random sequences. For decades, the undisputed king of multiple access was Code Division Multiple Access (CDMA), which relied heavily on binary mathematical constructs known as Gold Codes. But as we...
A few years ago, I acquired a box of Vaisala RS80-15G radiosondes from eBay. A radiosonde is typically attached to a helium or hydrogen balloon and released into the atmosphere. As it ascends, it measures atmospheric pressure, temperature, and humidity and transmits that data back to a ground receiving station. These observations are foundational for weather forecasting. In the Vaisala RS80-15G...
In my last post Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing, I designed, simulated and manufactured a Interdigital microstrip bandpass filter for the 5.5 GHz microwave band. One common issue with microwave filters designed for a specific frequency is the presence of spurious out-of-band responses, often occurring at harmonic frequencies...
Microstripline filters are essential components in RF and microwave circuits, offering a compact and efficient way to shape frequency response. In this post, we’ll walk through the complete process of designing, simulating, fabricating, and testing a microstripline filter. Starting with electromagnetic simulations in Ansys HFSS, we’ll validate the design before exporting it to KiCad for PCB...
I’ve always wanted to model the effects of a choke balun on a balanced dipole antenna fed by an unbalanced coaxial feed line. In particular, I wanted to model the antenna and feed system using EM software in order to visualize the electric field and current along the conductors in the system. Essentially, I wanted to prove to myself that the concepts that I’ve seen in literature and...