Questions tagged [microwave]
Microwaves are radio waves with a frequency from 300MHz to 300GHz which corresponds to a wavelength of one meter down to one millimeter. Often in RF engineering however it is used to refer to a narrower region such as 1 to 100GHz.
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How to measure antenna S21?
Please explain in detail how to take an S21 measurement for an antenna? I know what it is... but how do I physically connect the antenna to the VNA to take the measurement? Thank you in advance!
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Will a microwave induce current in a transformer placed inside of it?
If a transformer, say your typical 12v wall wart. were to be placed inside a microwave and then power the microwave, will the microwaves induce current in the transformer? What will happen to the ...
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Scattering Parameters and different load
I am somewhat confused as to the correct usage of s-parameters. Looking at the problem statement below, would the S-parameters given need to be "transformed" due to the load impedance being different ...
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What is the simple meaning of TE10 waveguide [closed]
What does this numeral 10 represents and why do we have TE10 TE11 and then TE20. Where are the rest?
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Using an Inductor as an antenna at UHF range
I'm a 6th form student from England. I am working on a special project that would require electrical signals with high voltage (in orders of kilovolts) at microwave frequencies (eg 2450 Mhz).
I was ...
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Radio signal flows through glass
With these antennas; how does the signal flow through the glass?
Is it also possible across other bands; like 2.4GHz Wi-Fi signals?
Specifically tuned for the 4G NextG / 3G spectrum for optimum ...
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Are TV coaxial cables compatible with WiFi antennas?
If I replace an old, roof-mounted TV antenna with a 2.4GHz WiFi (IEEE 802.11) antenna; can I use the existing coax? Or will I need to run all new cable?
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Microwave Waveguide system tuning
I am going to built microwave system with following system configuration.
Power Circuit -> Magnetron -> Wave Guide Coupler -> Isolator -> 3 Stub Tuner -> Applicator.
Now, I want to make 3 Stub ...
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Gunn diode operation frequency
Gunn diodes are usually specified to work within a range of frequencies, e.g ~10GHz. I can easily understand why there is an upper bound for the frequency of operation of a Gunn diode, but I can't ...
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What does "re-entrant cavity" mean? How is it different from "normal cavity"?
In the field of microwave engineering, what actually does "Re-Entrant Cavity" mean? How is it different from normal cavity? What is its structure?
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How can S11 component measurement circuit be made on a pcb?
I have a material whose dielectric properties need to be measured. I have done literature review on the physics & impedance based methods to determine the dielectric component.
It requires S11 ...
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speed of light and microwave in air [closed]
I was thinking that speed of light and speed of microwave should be equal (since I think they are same! I am not expert on physics), but due to my calculations:
speed of microwave in the air coming ...
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Efficiency of the microwave oven
Unloaded power transformers consumes very little real power. Similarly, will an empty microwave oven consumes very little power too compared if it is loaded full with food?
If this is true, can we ...
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How to create a dual zone microwave sensor
There are these microwave sensors in car alarms that have dual zone. This means that they can detect movement both outside (a small distance) and inside of the car.
How are they implemented?
I ...
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Why is Kapton film used to hold liquid in waveguide?
I am working on a project similar to the one described in this paper
MEASUREMENT OF COMPLEX PERMITTIVITY OF LIQUIDS.
Here a Kapton film is used to hold liquids, so that they don't spill. Why is this ...
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Reusing an 8 bit microprocessor? (86CH09NG)
I salvaged some parts from a microwave and I am wondering if it is possible/ feasible to reuse the 8 bit microprocessor on it? I am also not sure if I found the proper datasheet for it? (link to ...
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RFC realization for bias of microwave transistor circuits
I saw the following configuration for the bias circuit of some microwave amplifier circuits.
I think in the left figure the RFC is realized using a quarter wavelength short circuited stub (because of ...
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How to calculate return loss of the cascaded system?
If system 1 has 10 dB return loss and system 2 has 20 dB return loss then what is the overall return loss of cascaded system of 1&2 ?
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How powerful(in terms of output watts)can current Gunn diodes get?
That is, if I wanted a Gunn diode in the low GHz range with a 20kW output does such a device exist? If not what kind of semiconductor materials would be needed to support ballistic transport at high ...
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How to find the polarization (phase) of the virtual source if image theory is used
Consider a radiating element (actual source) is placed above a ground plane, and if we apply image theory to determine the E-filed, the virtual source will be placed below the ground plane and ground ...
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Quantifying white noise with a spectrum analyzer
The setup of my problem is as follows. I have an experiment in which I want to apply a noisy voltage with a white (flat) spectral density over a large frequency range, say 0 to 7 GHz for example. Not ...
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Actual procedure used to establish a MW link budget in telecom?
If it possible can someone share with me the actual procedure used (Not the theoretical steps in book !) like in Huawei or others telecom vendor to establish a Microwave Link between to sites
Like ...
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transmission line theory, complex conjugate matching
Referring to the below output matching network of an amplifier ,in which gamma_out is chosen as the complex conjugate of gamma_l (in the figure Γ and Γ*) in order to achieve maximum power transfer ...
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How to make an impedance matched circuit for fabbed antenna?
Okay I have developed an antenna for a system and need to create an impedance matching circuit. The theory of conjugate matching is simple, but actually implementing it is something I can't find ...
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Pinout of microwave motion sensor FC1816
Please, help to figure out the pinout of microwave motion sensor FC1816.
The seller "doesn't understand" what it is required on queries to provide the pinout for the module. The module is the ...
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Phase noise measurement with IQ mixer
I have a question regarding a measurement scheme of phase noise that I'm trying to implement. The idea is that I have two identical signal generators (I actually do) that generate a sinusoidal voltage ...
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Distributed Transmission Line, Characteristic Impedance in AWR Microwave Office
I am trying to design a distributed amplifier in which the parasitic capacitances of a small-signal FET model are linked to inductors to form a distributed line across the drains and gates and I'm ...
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Is a microwave's output power proportional to the mass of its contents?
My friend and I are having a heated debate.
On the one hand, he thinks that a microwave oven that is empty, consumes almost no power (not considering lights, lcd, etc). He says that once you put an ...
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GaN pulsed operation
Does anybody have experience biasing and pulsing a microwave GaN HEMT? I've just ordered a 10 Watt S-band transistor. I know all about bias sequencing. This application is pulsed. I've read about ...
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Smith Chart Conjugate Matching
In an example in Pozar's Microwave Engineering, a conjugate matching circuit for maximum gain is designed using Smith chart. In the shown Smith chart, the matching circuit for input is designed. We ...
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Is it possible to model a microwave resonator in SPICE [duplicate]
I just wanted to know if it was possible to model a microwave resonator in spice software or somehow import it from somewhere to spice to carry out analysis.
Also if it is not possible to model the ...
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Coupled Line Filter Design in Qucs
I'm getting to grips with designing coupled line filters and wanted to implement the band-pass filter described in Example 8.7, p. 435 in David Pozar's excellent "Microwave Engineering" just as a ...
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Output reflection coefficient of a two port network
In the third edition of the textbook Microwave Engineering by David Pozar, example 4.7, it is explained how to use signal flow graphs to find the output reflection coefficient \$\Gamma_{out}\$ of a ...
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LED characteristics to use in heating a material sample?
I am looking to be able to heat a sample of material, typically less than 500mg and sitting in a fused silica sample holder about 10mm diameter. Wondering about using (say) a 5W LED with narrow ...
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Function to Simulate Realistic Waveform
I need to simulate a realistic signal voltage triangle waveform in Mathematica. I know that a real waveform won't have sharp corners, but I don't remember exactly what a real triangle wave looks like....
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Why is a high-Q circuit difficult to match?
People in the microwave/RF field constantly talk about how it is "difficult" to match a high-Q circuit (ie. a CS amp with very little gate resistance and no degeneration). Why is that?
The problem is ...
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Why does microwave communicaion require line of sight?
What I can I think about is:
Power spectrum density at MW frequencies is very poor at a point it is unable to penetrate obstacle without losing a lot of power.
Multipath fading at those frequencies ...
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Signal speed through different materials
I've been tolled that signals are carried by electromagnetic waves caused by oscillating charges, and that this action occurs in a manner similar to how billiard balls interact with one another.
I'm ...
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HEMT/PHEMT transistor circuit design- need manual/book
I have to design a microwave amplifier in the frequency range of 0-15GHz. To this end, I need to be able to design circuits with HEMT/PHEMT transistors. Is there a comprehensible manual that teaches ...
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Microwave amplifier characteristics - don't undertand [closed]
Please, look at http://www.rfcomp.com/hd24223.aspx (the spec file is downloadable in this page). This is a microwave amplifier, and I have several questions.
1) What is "noise figure" ?
2) What ...
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Electromagnetic or microwave cooling
Heat means stored kinetic energy in matter. Microwave owens and induction heaters works on increasing kinetic energy on matter. Is it possible to make inverse of this heaters like cooler. We can ...
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Why do we need a waveguide in a microwave oven?
Why do we need a waveguide to move microwave power from the magnetron to the microwave cavity?
Can't we just push magnetron antenna into the cavity?
Why does it have to go through a waveguide?
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Relation between reflection (coefficient) and bandwidth
I am reading into single stage microwave amplifiers and how to design for a specific gain (source 1, source 2 warning PDFs!). In both sources the claim is made that the highest bandwidth is achieved ...
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Explanation for stability criterium microwave amplifiers
Given a general microwave amplifier circuit
For this amplifier (transistor) to be stable the the magnitude of the input and output reflection coefficient must be smaller than 1.
But why? What is an ...
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EM wave polarization check
I am trying to recall the quick way to check the EM polarization theoretically, I mean if I have a wave described as (ssume capital letters are vectorial fields)
\begin{equation}
\ E = E_o *exp(j* \...
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Microwave oscillator conditions
The conditions for a negative resistance microwave oscillator are (2-port):
\$K < 1\$ (unstable device)
\$Γ_{in} \cdot Γ_g = 1\$ (condition for oscillating input port)(generator side)
\$Γ_{out} \...
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Microstrip length problem
I'm simulating a single microstrip half-wave resonator (1.8 GHz) in Sonnet and using ADS LineCalc tool for calculating the microstrip length but I'm getting a wrong number.
Substrate parameters (...
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Uneven (10 dB) RF Power Splitter/Combiner
I'm trying to modifying and improve the MIT radar project
Here's the basic block diagram:
Input power is split by 3 dB SPLTR1 to transmitting antenna and LO input to the mixer. From what I ...
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40 GHz spectrum analyzer with N-type coax input?
We have an old Rohde & Schwarz FSEK 30 that is advertised as having a range from 20 Hz to 40 GHz, with an N-type input connector. My conundrum is that a type-N connector with air dielectric ...
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How does a microwave oven-leakage detector work?
What type of sensor or circuitry is inside one of these devices that allows measurement of microwave radiation strength? I've never opened one but I'm assuming it's similar to measuring RSSI on a ...
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