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Orthomode Transducers: Part 1 – Introduction and Applications David W. Porterfield, PhD Founder, Micro Harmonics Orthomode transducers (OMTs), also known as polarization duplexers, are waveguide components that combine or separate two orthogonally polarized signals. OMTs have three waveguide ports. Two of the ports support a single propagating mode, typically the TE10 mode in rectangular waveguide. [...]

A mm-Wave Circulator with High Transmitter and Receiver Isolation (Part 2) David W. Porterfield, Ph.D. President and Founder Micro Harmonics Corporation In last month’s blog, I showed why a triple junction circulator offers no advantage over a single junction circulator in isolating a sensitive receiver from a high-power transmitter (S31). I also showed that the [...]

A mm-Wave Circulator with High Transmitter and Receiver Isolation (Part 1) Circulators are used in transmit/receive systems to allow a transmitter and receiver to share a common antenna. A circulator schematic is shown in Figure 1, with typical connections for the transmitter (Tx), receiver (Rx), and antenna (Ant). Figure 1 – Schematic for a circulator [...]

Are Faraday Rotation Isolators Sensitive to Magnetic Fields? Some Faraday rotation isolators are very sensitive to magnetic fields while others show almost no sensitivity at all. It depends on the magnetic bias point. Faraday rotation isolators employ a magnetically biased ferrite rod. An internal magnet or an array of magnets is used to bias the [...]

Do mm-Wave Power Amplifiers Need Isolators? The answer to the question is often yes. It is common to see a mm-wave power amplifier with an isolator attached to the output port. The reason may have less to do with the impedance matching of the amplifier and more with the impedance matching of the load. The [...]

Radiation Testing of Micro Harmonics Isolators Space exploration has always pushed the boundaries of technology, requiring instruments that can withstand the harsh conditions beyond Earth’s atmosphere. One of the critical factors that must be considered when designing space-based instruments, such as isolators, is their ability to endure the effects of radiation, particularly the Total Ionizing [...]

Multipaction Analysis for Millimeter-Wave Isolators and Hybrid Circulators Multipaction [1, 2] is a phenomenon occurring primarily in RF systems operating in a vacuum such as those found on space-based platforms. RF fields accelerate charged particles (electrons) which gain energy and collide with surfaces. If the impact energy is sufficient, additional electrons are released from the [...]

Why Are Y-Junction Circulators Difficult to Find Above 100 GHz Y-junction circulators are used to direct signal flow in millimeter-wave (MMW) transmit and receive systems. At the heart of the device is a ferrite core located at the junction of three waveguides. The magnetically biased ferrite is non-reciprocal which gives rise to the unique circulator [...]

Fullband mm-Wave Circulators Are on the Horizon Diving into Revolutionary Circulator Developments Circulators are useful in transmit/receive systems, isolating a transmitter from a receiver while allowing them to share a common antenna. For more than 50 years the Y-junction circulator has been the primary implementation at mm-wave frequencies. Commercial Y-junction circulators with full waveguide band [...]

Revolutionizing MMW Systems: The Crucial Role of Cryogenic Isolators Millimeter wave engineers operate in a part of the electromagnetic spectrum where there are some significant challenges to overcome. It is difficult to generate signal power, the available components are costly and sometimes don’t work well, and often the components just don’t exist at these frequencies. [...]