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Questions tagged [rf-electronics]

51 questions
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How to calculate permittivity for higher frequencies?

In many books the permittivity of a material is only listed as dielectric constant for one or a couple of frequencies. 1 kHz is used often (for example in the Plastics Technology Handbook, 4th ed, ISBN-13: 978-0-8493-7039-7), but I'm looking for the…
Mast
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6
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1 answer

What is Byte Alignment Time in radio communication?

According to this paper, which deals with time synchronization in wireless networks, this kind of delay occurs, however I do not understand its explanation. The paper says the reciever (radio) has to determine the bit offset of the message from a…
sifear
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6
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1 answer

Are there any differences between using nylon or ABS for RF electronic cases?

I want to contain a very small PCB (roughly a square centimetre) in a casing. For demonstration purposes I want to 3D print a couple of those casings as well. The most obvious method available would be using ABS for the printed casings. However,…
Mast
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5
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1 answer

Building RF power meter

I want to build power meter for wifi signals. One way to do it is to use a diode to rectify AC signal and amplify that before measuring. But are there diodes which work at such high frequency? Also, are there other methods?
wfn
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4
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A material to insulate a container so that water inside the container is not affected by microwaves?

I'm running an experiment and I need to have a container filled with water. The container will be placed inside a microwave oven, but I need to minimize any effect the microwaves will have on the water. How can I go about running my experiment? I'm…
Robin Alvarenga
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4
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2 answers

Frequency dependence of electromagnetic shield metal

I know that the effectiveness of metals used for electromagnetic shields heavily depends on the used frequency or frequency range. I could not find a resource in the web (tables or graphs) that give me the information which material (especially…
Silicomancer
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4
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2 answers

Measuring the distance to an object with RF resonance

Assume I put an RF antenna in front of an object (typically the face of someone sitting in a chair, so able to move about +/- 10cm in all directions) at a typical distance of 1m. If I consider the system antenna/face as a resonant cavity, I'd get a…
Julien
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3
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How much current is this phone drawing?

I know the current should be higher than 0.67 mA, because I know phones use current in the order of 1A. Also the charger is able to support up to 1A, it doesn't make sense that the charger would have such a superior current than the phone will…
Nadim
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Methods of finding the angle to an object

I'm working on a project that needs a system that can determine approximate angle of an object related to it. I have anchor position (multiple anchors, but fairly close ~ 1m of each other). And object that moves in front of anchors (1m to 5m…
somerandomusername
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Evaluating bonding integrity of piezoceramic transducer

Currently I am working on a Structural Health Monitoring system utilizing piezoceramic transducers. The proof of concepts have worked very well. But we are in the process of working small scale manufacturing. We have observed inconsistency in the…
Nil_2018
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How to design a 915 MHz waveguide circulator?

I would like to design a waveguide circulator. I tried to design one but, my attempt was not successful. My design used a cylindrical cavity with ferrite as region. I then connected 3 waveguides in 0,120 and -120 directions. Upon applying the…
sumith
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Detection of weak signal by satellites

An animal's blood pressure and/or body movements can be used to generate a few mW of electrical energy. Can an RF transmitter which radiates 1 mW be detected by receivers (without any parabolic reflectors) on satellites? The receiver has to only…
wsxcde
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Low bandwidth electronic filter

Is it possible, under current technology, to have an electronic filter in the microwave range (100 MHz to 300 GHz) with very low bandwidth , say 100 to 1000 Hz? If yes, then what is the basic technology behind it? Any example would be great.…
ikjhb
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Is there any hardware to use in GPR applications?

I want to make a radar system which needs to send EM wave and receive the reflected wave from the ground. I am looking for a ready to use RF signal processing hardware but can't be sure which is applicable. As I found that, the required frequency…
freezer
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2
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A 40MHz oscillator in usb wifi adapter

I disassembled a usb wifi adapter. I was surprised to see a 40MHz oscillator, when wifi works at 2.4GHz. How the output of the oscillator is scaled to the required frequency?
akm
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