Questions tagged [rf]
Short for Radio Frequency, i.e. frequencies at which radiation (intentional or not) plays a role. Typically associated with wireless communications, but also relevant for high-speed PCB design.
4,253 questions
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Best approach to sweep 410-525 MHz? PLL/VCO vs ramped timer vs sweep-IC? [closed]
I need to implement a frequency sweep covering 410-525 MHz. I’m considering several approaches but want advice on real-world practicality: Simple ramp voltage → timer IC → ??? (drive a timer or ...
1 vote
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SMA Edge Mount Connector Placement
I would like to measure the input/output impedance of some circuits from 1 MHz-200 MHz using a nanoVNA. PCB stackup is Sig/GND/GND/+5V, Sig does not have a ground pour on the same layer. Trace width ...
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Modeling RF Impedance Matching PCB Geometry
I am designing RF amplifiers, and I often use LDMOS transistors with unmatched inputs and outputs. My goal is to learn how to model and simulate PCB impedance-matching geometry on a computer before ...
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How to layout a transmission line for impedance matching when using a chip antenna
I will be designing a PCB layout for a LoRa module very similar to this one, but with a chip antenna instead of a U.FL connector. It seems that this one has a pi matching network for matching the ...
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433.92 TX 12V Prototype Review
I have been using 433 RF TX ICs that work well at 3.3V however I wanted to try and test out a 12v 433 TX circuit. Only digital AM ASK/OOK used. I'm running my circuit on a LiPo battery so I though the ...
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1 vote
1 answer
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Choice of PCB Material for HF RF circuit
I am currently designing an FM Radio (88MHz - 108MHz) and have gotten to a point in the design where I am beginning the layout plan / make some general design decisions about manufacturing. I plan to ...
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1 answer
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Purpose and selection of inductor for RF power amplifier that has a VCC pin (MAX2616)
I am currently building an RF amplifier PCB for around ~2.4 GHz using the MAX2616, which is a broadband RF amplifier for 40 MHz to 4000 MHz. Looking at the datasheet, I am confused about the purpose ...
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Very low RF-DC conversion efficiency in ADS (SMS7630 & HSMS-282E)
Simulating RF rectifier in ADS (2.45 GHz, 5 dBm). Using HSMS-282E gives 11% PCE, SMS7630 gives 20% PCE. Matching is correct (good S11). Using SPICE models from datasheets. Load = 2 kΩ. Using HB with ...
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how realistic is my radioastronomy setup? [closed]
My plan was to have 2 rx antennas inside 2 coffee cans (cantenna setup), then possibly an LNA on each one (probably spf 5189), then going into the rx1 and rx2 of a pluto+ SDR. each cantenna would be ...
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1 vote
1 answer
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Bluetooth Antenna Characteristics
When looking at an antenna datasheet, there is a polar plot (below image) that shows the antenna's characteristics in different planes. I would like to know what this plot represents. Is it EIRP, ...
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Designing first RF circuit and wondering how to pick passive components on the RX and TX line
This is the first time I'm doing stuff with RF and I am using the STM32WL30KBV6. I plan on using it for LORAWAN communication but I'm having trouble figuring out what passive values I should be using ...
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How are the shunt coupling capacitors chosen in this double-tuned HF bandpass filter, and how do they affect the resonance and bandwidth?
I am studying a tunable double-tuned band-pass filter used as an HF preselector. A reference implementation is here: http://www.qrp.gr/hf_allband_filter.htm The topology is: Two LC resonators (left ...
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1 answer
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Getting a radiation pattern plot from a phased array digital beamformer
I constructed an antenna device (2RX 1TX) from this Jon Kraft video for an ongoing project in an anechoic chamber. In all honesty, my knowledge in this area is quite limited and I'm a getting a bit ...
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-1 votes
1 answer
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RF test connector signal leakage
I'm trying to quantify Wi-Fi throughput of a link consisting of two devices. One of the methods is connecting the devices using standard test connectors MM8030-2610RJ3, a coaxial conductor and a ...
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Correct S21 for a Port-2-mismatch
I have a 2-port device with the following S-Params: S11 = -41.1 dB S21 = S12 = -32.7 dB S22 = -0.0099 dB In other words, Port 1 is (perfectly) matched, but Port 2 not. If I change the device to having ...
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