Applied RF Design & Digital Signal Processing
Deep-dive technical explorations from 3D electromagnetic HFSS simulation and microwave PCB fabrication to 5G waveform synchronization, software-defined radio decoding, and embedded architectures.
Featured Technical Article
May 16, 2026
Clash of the Telecom Codes: Zadoff-Chu vs. Gold Sequences
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....
Engineering Articles & Lab Notes
Complete archive migrated from radix2tech.com with compile-time KaTeX math & high-resolution plots
GPS Quadrifilar helix antenna model
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...
Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing – Part 2
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...
Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing
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,...
balanced dipole fed by unbalanced coax
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...
How Digital Data Is Transmitted Wirelessly – Part 1
Digital data can be transmitted wirelessly over an analog channel in various ways. Let’s start with an explanation of digital data. Digital data in modern information systems is also known as binary data, which is...
the matched filter – a quick analysis and example
The matched filter is one of the most useful tools available to the Digital Signal Processing (DSP) engineer. Matched filtering maximizes the Signal to Noise Ratio (SNR) of the filter output when a signal matching a...
A z80-based Embedded Design – Hot Tub Heater
The 8-bit Z80 microprocessor has been a popular choice for early computer designs and continues to see some use in embedded systems today. When I was 14 years old, my Dad purchased a Commodore 128 as an upgrade to...
6502 Assembly Language State Machine
In December 1982, Santa delivered a Commodore 64, which became an obsession for me during my childhood and teen years. I quickly discovered that most of the graphic operations I wanted to perform were not possible...
Hacking the Signal from a Remote Control Dog Training Collar – Part 1
I picked up a remote control training collar for our 7 year old Maltese to help train her in order to curb barking. In the spirit of keeping everything humane, we only use two of the three functions (alarm, vibrate,...
Hacking the Signal from a Remote Control Dog Training Collar – Part 2
This is a continuation of a previous post https://radix2tech.com/decoding-an-rf-dog-barking-control-collar/ in which I examined the signal characteristics of a non-branded dog training collar. I purchased an...