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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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Simple method to generate nonuniform magnetic radiation in a region of 0.5 mm?

I need an antenna that can generate a nonuniform magnetic field over a very tiny region at 5 GHz. (By nonuniform, I mean that the field vectors are diverging as much as possible. I will place this ...
Steven Sagona's user avatar
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0 answers
61 views

Microwave magnetron connections reversable F, FA?

The two connections on a microwave magnetron are labeled F (filament) and FA (filament anode), both being either ends of a heated filament powered by a 3V AC supply, and the FA connection being ...
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Transmission Lines and Waveguides - How to calculate Intrinsic Impedance?

I have come across a problem when calculating the attenuation due to conductor losses for circular cross sections: A circular copper waveguide has a radius of 0.4 cm and is filled with a dielectric ...
Meeth's user avatar
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1 answer
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Troubles in understanding the TGA2214-CP microwave power amplifier datasheet

The datasheet of the Qorvo microwave amplifier is here. I have troubles with the following points: In p. 9, they give a schematic of the way to mount the amplifier (I believe). But at the end of the ...
MikeTeX's user avatar
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1 answer
127 views

Time average stored electric energy in a volume

I am studying the book Microwave Engineering Third Edition by David M. Pozar. At the moment I am at chapter 1.6. At the beginning of this chapter Pozar states that In the sinusoidal steady-state case,...
CircuitMan's user avatar
1 vote
1 answer
47 views

Substituting for 1N34A diode to change range of microwave detector

In connection to an earlier question, this DIY device for detecting "mini radio" EMF seemed like it might work to detect microwaves generally, assuming diodes exist to replace the 1N34A ...
daniel's user avatar
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1 vote
1 answer
111 views

How can I visualize 24 GHz RF on a screen?

Is there a (preferably inexpensive) way to visualize/image 24 GHz RF from a radar gun (of the type used to check baseball speeds) on a screen? Here are some examples of what I mean, for other ...
daniel's user avatar
  • 145
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1 answer
45 views

Add resonances to monopole antenna

How can I design a "simple" low frequency monopole antenna with multiple resonating frequencies? I elaborate... I need to design a sort of monopole antenna with multiple resonating ...
Shika93's user avatar
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2 answers
49 views

S-parameter of cascaded system, port impdance

I have a question about the s parameter of the cascades system. Assuming that there are two system A,B as shown in the figure and each has an s-parameter measured at 50ohm port, I understand that the ...
ogologol's user avatar
1 vote
0 answers
46 views

De-Embedding Structures

I am trying to de-embed the attached ports and gnd plane to measure characteristic impedance of transmission lines in between the two port/small TLs. I have tried techniques on https://www.doe....
user369123's user avatar
0 votes
2 answers
73 views

EMF Meter: difference between AC magnetic, AC electric, and RF Measurements

let's consider this EMF Meter. Regarding its description, I have some doubts regarding what it is physically trying to measure: Detects all three types of EMF pollution: AC magnetic, AC electric, and ...
Kinka-Byo's user avatar
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4 votes
2 answers
234 views

Microwaves going through a hole - attenuation?

We have a microbalance that has a "hangdown wire" supporting a sample pan in a steel chamber. We need to heat this with microwaves, most probably at the common 2.4GHz of microwave ovens. ...
Dirk Bruere's user avatar
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Using microwaves to dry a small sample of material - best method?

We have a requirement to use microwaves (no choice here) to dry a small sample of material with a mass not exceeding one gram. It will be placed in a small sealed steel enclosure. First thoughts were ...
Dirk Bruere's user avatar
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1 vote
1 answer
161 views

Two-way Wilkinson divider: why is R₂ = Z·K and R₃ = Z/K?

I am trying to understand why R2 = K · Z0 and R3 = Z0 / K. I get the power is not equally distributed over both ports, but why is one multiplying and the other dividing?
Sam Shurp 's user avatar
1 vote
1 answer
142 views

Intuitive explanation of shorted stub behaviour

Can someone please give me an intuitive explanation of shorted stub behaviour? NOTE: This is not a duplicate of Intuitive explanation of open stub behaviour which has been narrowed to focus on open ...
Curious Cosmopolitan's user avatar
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2 answers
195 views

Intuitive explanation of open stub behaviour

Can someone please give me an intuitive explanation of open stubs? I have the length-based mathematical derivation and explanation from my textbook, but I am looking for an intuitive one. For example,...
Curious Cosmopolitan's user avatar
4 votes
2 answers
296 views

Can I test the EM shielding of a material with a spectrum analyzer?

I am a hobbyist and I am intersted in testing some materials for their ability of reflectance/absorbance/transmittance for microwave radiation and I want to know if a spectrum analyzer is suitable ...
Tintin's user avatar
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Keysight ADS layout error "port pin not connected to conductive part of design"

I just designed a distributed element BPF using ADS and now I'm trying to put it into the layout to do an EM simulation. I created my distributed circuit using the dimensions of my components, then ...
TheBelgianWaffl _ Gaming's user avatar
1 vote
0 answers
68 views

Integrated Circuit z-impedance

I have an OBU (On-board Unit) circuit and it has a DSRC (Dedicated Short-Range Comm) IC, but I don't have any information about the IC from S11 and Z etc. I want to ask how can I find the Z-impedance ...
Alan Alan's user avatar
0 votes
1 answer
85 views

Finding datasheets for relatively new looking components but nothing appears from search

Some context: I acquired some RF components from the family of an old RF tech that passed. I am currently adding the parts and datasheets to my inventory but for the following parts I was unable to ...
Pxl's user avatar
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3 answers
96 views

AD application note MT-097

Below is the statement from AD application note MT-097. I have see this explanation many places. But no one explains how transmission line effects comes when rise time is smaller than 2*times ...
Confused's user avatar
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35 views

What phase-noise can I expect for high-end microwave sources?

I would like to know what type of phase-noise I can expect if I want to be able to produce a single RF frequency source. It does not have to be tunable, it just needs to be around 10 GHz. What is the ...
Steven Sagona's user avatar
1 vote
0 answers
47 views

Matching network for two-port with internally matched inputs/outputs

Background I had a lab in school where we were given an LNA with inputs/outputs matched to 50Ω, that will be connected to a 50Ω system: The task was to design the input and output matching networks: ...
Hugo Lundin's user avatar
6 votes
2 answers
478 views

Monopole antenna with coil design

(Note: I'm a beginner in antenna theory) When browsing for low cost antennas online, there seems to be class of monopole antennas that have a coil or two built into the monopole, and are advertised to ...
小太郎's user avatar
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2 votes
1 answer
82 views

Microwave output power seems inconsistent with supply voltage

In this document, the author says in the last page that his amplifier output is 3.8 W. But looking at the schematic, the input voltage of the transistor is at maximum 12 V. Taking into account that ...
MikeTeX's user avatar
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1 vote
1 answer
66 views

3 dB Power Divider Used as Power Combiner S Matrix Explanation

I'm trying to understand the operation of an ideal RF power combiner. Below is the scattering matrix of such device. (i.e. Wilkinson Power Divider) \$[S] = {\frac {-j}{\sqrt {2}}}{\begin{bmatrix} 0 &...
Exclose's user avatar
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2 votes
3 answers
1k views

Why do amplifiers have minimum frequencies?

RF amplifiers, both power amplifiers and low noise amplifiers, are rated with a minimum and maximum frequency. For example, the Analog Devices HMC517LC4 Low Noise Amplifier has a frequency range of ...
SRobertJames's user avatar
1 vote
1 answer
120 views

Microwave oven control board not working [closed]

I am attaching two pictures of the control board. Can someone explain why the positive output from transformer is going to ground while negative output is going to the voltage regulator. The negative ...
Muhammad Waqas Hafeez's user avatar
1 vote
1 answer
131 views

Derivation of input admittance of a lossless T-Junction Power Divider that is matched at the input port

I'm trying to understand how the equation for the input admittance for a lossless T-Junction power divider was derived, which is only matched at the input. Let \$Z_0\$, \$Z_1\$, \$Z_2\$ be the ...
McSuperbX1's user avatar
1 vote
0 answers
60 views

Real World Range of C-Band (3.7Ghz) versus EBS/BRS (2.5Ghz) mid-band 5G

I am aware that with all things being equal, lower frequencies propagate better. Thus, T-Mobile’s 2.5Ghz spectrum should have better range than AT&T’s and Verizon’s 3.7Ghz spectrum. T-Mobile ...
Jeremy Lund's user avatar
0 votes
0 answers
34 views

On-chip Co-planar Waveguide Design on Si – SiO2 Substrate

I want to design, simulate, and fabricate on-chip Coplanar waveguides (no bottom ground) on a Silicon Dioxide layer 5um thick on a Silicon 500um thick wafer. The metal electrodes will be 1um thick ...
Ravi Pradip's user avatar
2 votes
3 answers
384 views

Scattering matrix of quarter-wave transformer

I am trying to solve for the scattering parameters of a quarter wave transformer. The example that I am given is a transformer with characteristic impedance 100 Ohms, and the reference impedance (...
ff18192021's user avatar
1 vote
1 answer
140 views

Problem understanding lossless T-Junction divider

I am studying how the lossless T-Junction divider works. I am going to assume that the susceptance in the junction is 0 for simplicity, and it is not relevant to my question. The structure of a T-...
fraghotmailcom's user avatar
1 vote
0 answers
107 views

Interdigital filter ground connection on PCB

I have used an online designer utility for my 5 GHz to 6 GHz RF output filter, on the schematic it generated it had shown ground attach points, but I am not sure if I designed ground connections and ...
thegamebusterpl's user avatar
1 vote
0 answers
36 views

Are transistors on MMICs considered lumped elements?

Are transistors, in practice, always small enough to be considered lumped elements in Monolithic Microwave Integrated Circuits (MMICs)? Similarly for discrete transistors used in hybrid microwave ...
jramsay42's user avatar
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2 votes
2 answers
186 views

Visualizing current flow in transmission line

This may be a trivial question, but I am not sure how current flows in certain types of transmission lines. Consider for example a coaxial cable working in its TEM mode. The wave travels perpendicular ...
fraghotmailcom's user avatar
2 votes
1 answer
123 views

The effect of the wavelegth on the receiving power in Friis equation

In the Friis transmission equation, $$\frac{P_r}{P_t} = G_t G_r \left( \frac{\lambda}{4 \pi d} \right)^2,$$ it seems that if the frequency is halved while the other parameter values are fixed, the ...
adba's user avatar
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0 votes
1 answer
224 views

How can I limit the active working angle on a microwave motion sensor?

I have a microwave motion sensor that can be triggered in almost every angle. I want to limit its angle of view to only one side of the board but so far I had no success. What I have done: Designed ...
AKTanara's user avatar
  • 291
0 votes
0 answers
89 views

How can I identify this microwave circuit?

I found this microwave circuit from e-bay but cannot identify what this circuit is doing. I am asking this question since I found the same circuit from the sampling scope that I was tearing down in ...
Emm386's user avatar
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0 answers
61 views

Is there a device to generate a sequence of microwave harmonics?

I want to produce a Fourier series of microwave harmonics in a cavity. My first thought was to order a bunch of magnetrons tuned to each harmonic, up to some limit and get our lab tech to modify a ...
holyjoly's user avatar
1 vote
0 answers
40 views

Ferrite bead in Gunn multiplexer

This link shows (at bottom of page) a simple Gunn diode circuit. My question is about the "ferrite bead" at the right. It seems to be an inductive coil with increased resistivity (?) near ...
daniel's user avatar
  • 145
1 vote
0 answers
80 views

How to simulate a Large Structure at low frequency in CST Microwave Studio?

In CST Microwave Studio, I attempted to simulate a large (215x30cm) loop structure at 1kHz. However, CST gives a warning of 'too large' mesh size. The mesh size increases up to 6 Billion, however, if ...
Pessentrau Optiarou's user avatar
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0 answers
22 views

How can I improve "SNR" in a measurement of noise power?

I'm doing an experiment where I need to use a shot-noise tunnel junction as a calibrated noise source to characterize our measurement system. This is done by sweeping the voltage across the SNTJ and ...
ttshaw1's user avatar
  • 15
3 votes
2 answers
376 views

Origin of square law behaviour in Schottky diode microwave power detectors

The instructional schematic for a Schottky diode power detector is usually given as something like this (see eg page 2 of this pdf, or this page), where the detector consists of the diode and ...
llama's user avatar
  • 578
1 vote
1 answer
113 views

Characteristic impedance: TDR (function of position) versus VNA (function of frequency)

A TDR gives you the characteristic impedance of a transmission line as a function of position. You can also measure the characteristic impedance of a uniform transmission line using a VNA, which gives ...
qtc0's user avatar
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0 answers
54 views

Using 2.4 GHz microwaves to demonstrate optical polarization

Several educational companies sell kits to demonstrate optical polarization using 3 cm (10 GHz) microwaves emitted from a Gunn diode transmitter and simple grid-like polarizers. My question is whether ...
daniel's user avatar
  • 145
-1 votes
1 answer
783 views

Could a DIY 1 kW portable version of the military non-lethal microwave beam active denial system (ADS) be made?

How would one create a portable 1 kW microwave emitter that projects out a 95 GHz beam to about 5 - 10 feet? What kind of components would be required? I recently came across this fascinating video ...
emtinkerer's user avatar
0 votes
2 answers
187 views

How to generate microwave band frequencies like 85GHz? Is there a DIY device or parts kit to do this? [closed]

Let's say I want to build a device that generates and sends out a microwave of some arbitrary specific frequency to a short distance, say 1 - 2 feet. For example, 95 GHz. Is there a straightforward ...
emjunkie's user avatar
4 votes
1 answer
643 views

Is my VNA broken or miscalibrated, or are these weird results normal?

My company got a new vector network analyzer recently and I'm using it to try to learn more about microwave circuits, especially the resonant cavities that we use in our measurement systems. I've seen ...
Adam Haun's user avatar
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1 vote
0 answers
55 views

What does the value of R_t represent in Balanis' bowtie antenna design equations?

I'm using Antenna Theory: Analysis and Design by Constantine Balanis to aid in the design of a wideband antenna. I believe a bowtie antenna will satisfy my necessary bandwidth, however Balanis notes ...
Gabe S.'s user avatar
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