Questions related to RF Technologies
I know that I should compare their actuation voltage, capacitance ratio, and S-parameters. Apart from the mentioned characteristics, are there any other ones that I should compare?
Dealing with a helix antenna, made with flexible material and not rigid like using a PCB board or wire. At the beginning of the helix is too close to the ground plane, causing coupling. How can I get rid of this inductance problem, if I cannot use a PCB board design here.
As part of my research, I need to couple a loaded, custom-sized, rectangular, waveguide (in which a hybrid mode propagates at 8.5GHz) to either a) a coaxial transmission line or b) to a standard X-band waveguide.
I need to understand the design and optimization processes for both including impedance matching and/or mode conversion as required.
What is the best, most efficient way of approaching such a task?
Any useful resources on the topic would also be very much appreciated.
I am unable to quantify the role of passive components when it is attached with the antenna. For various frequency bands like L,S,C,X the specifications of the active circuits changes but what will be the change in passive components and the antenna with respect to the frequency band.
Kindly give some answer or link , I am fully confused and I have to make a RF transceiver for demonstration purpose for the above mentioned frequency band.
If I get the block diagram with specs, it will be highly appreciated.
I hope I will get the answer at the earliest
Coherer behavior, especially RF (Radio Frequency) coherer behavior, has defied explanation for more than 120 years. Many researchers have postulated that quantum tunneling may the mechanism by which small amounts of RF energy, applied to a coherer biased at a DC voltage difference much less than required to cause cohering, is the root cause of the conductivity increase that made coherers the first commercially viable RF detector. I believe that the first person to suggest quantum tunneling in one form or the other was responsible for coherer behavior was Angelika Maria Josefa Székely de Doba in 1924. Marconi employed coherers to detect very faint RF Morse code signals transmitted across the Atlantic Ocean.
Angelika Maria Josefa Székely de Doba ; Über die Art des Elektrizitätsüberganges zwischen Metallen, die sich lose berühren [On the Types of Electrical Behavior between Metals in loose Contact]; Zeitschrift für Physik; Vol. 22; February-March 1924; pp. 51-69.
I need to calculate the dispersion curve for a cylindrical waveguide partially loaded with an artificial material. For reference at present I have papers by Brand (2006) and Rao (2007). Can anyone suggest:
a) Any other reference material that may be useful.
b) Any commonly used methods used to complete the calculation.
I’m looking for information or papers on the following:
The utilisation of RF technology in the human hand.
The utilisation of RF technology in manufacturing applications.
Some of the books have always been used as a standard reference in that particular field. I am looking for such book on active components design theory and analysis; and that could have system level implementation/examples/models.
I am a graduate student woking with Radiofrequency plasmas for chemical reactions and materials synthesis. I'd be extremely grateful if you can recommend me some literature or publications which can help me understand the selection of configuration and range of impedance for the matching network. Is there a way to measure the impedance of a chamber?
My reactor is Inductively Coupled Plasma using external RF coils and a quartz tube (1 inch) passing through the center of it. I'm trying to strike plasma in a 1/4 in OD tube but am not successful with it.
RF transparent materials are materials where RF fields can penetrate with no heating happen. So far, I know some like Teflon, PPL, PVC, and ABS. They are made of plastics and have almost 0 dielectric loss factor. Anybody can suggest and give opinion about this.
In general, the microwave oven employs 2.45 GHz and most microwave ovens have similar cavity. As I guess, the transmitting length isn't finite. However, how about valid distance of the conventional microwave? Some people said that radio waves expand out using the inverse square law, meaning that the strength is 1/(distance squared). Then, how much distance is valid to increase temperature of target if there is no door and just with waveguide? If there is any scholar equation or base data about it, I hope to know that. For example, using the governing equation concerning with energy transmition of microwave, quantitatively calculate them.
Furthermore, recent commercialized microwave ovens have a stirrer in the wave guide. The stirrer do a role of microwave diffusion as I know. But it may interrupt microwave transmission or decrease the energy for target. Isn't it?
For simulating a dual-polarized transition, a trial with a basic patch structure with 2 orthogonal microstrip line (MSL) feeds is used to excite orthogonal modes in a Circular Dielectric Waveguide above. As both the MSL ports should act as input ports, I have tried initially with sequential excitation which gives the results (S Parameters etc) for each excitation individually.
My queries in this context are:
1) In order to know the transmission to the Waveguide port on top due to excitation of both the input ports is simultaneous excitation the only way out? (Are the results of transmission characteristics of simultaneous excitation a sum of those due to individual sequential ones)
2) Having tried out simultaneous excitation too 'F Parameter' term is obtained. Could the precise meaning of they precisely mean be clarified?
I am reading about the capacitively coupled plasma but could not get any details explanation about the stochastic heating. Can I please get some elaboration of this method and hopefully if there are any good source materials. Thank you in advance.
I'm researching a concept and need some help. Let's say we have two objects. While the two objects are essentially the same, they each have a slightly different resonate frequency. Is it possible to broadcast a signal that would have an effect on one of the objects with negligible effect on the other?
I'm doing recognition of activities from RF-signals which is device-free and I'm using USRP device.So what kind of activities do you think is suitable to measure with,because during the experiments they are many interference and noises.
I would appreciate any help or insight or suggestions or ideas regarding simulating a WDCN based on 60 GHz wireless RF technology in MATLAB?
As far as I know, the coaxial cable has zero sum of current (sum of current between central conductor and outer shield conductor) thus inductance and radiation from the cable is very low.
However, I guess this current cancellation is only strictly true for DC. For AC, maybe phase of the signal has to be considered? Is this really true for AC such that current between two conductors are always in out-of-phase in principle? (I know real world is different from theory so I'm asking some comments rather involving principle first)
Do you know of any commercially/DIY available RF energy harvesting products besides those of Powercast?
I am a Physics person. I am stuck with this simple thing which could be very obvious. Please help me to resolve this issue.Cable Impedance of 50 ohm cable is always considered to be real in all calculations but the measurement of resistance by multimeter shows infinite which is obvious. Then, as we know that a lossless 50 ohm cable is modelled by many identical section which consists of series of inductance and parallel capacitance and the impedance is given by square-root of (L/C). So, how this real impedance of 50 ohm ( if it is real it represents resistance) comes into picture and why we cannot measure it by multimeter?
The concept of an "equivalent rounded obstacle" is used to account for radio propagation losses over various possible irregular terrain shapes, including
shapes which cannot easily be described geometrically.
I saw the previous paragraph in the attached paper, but I could not find any other useful document about this concept. Does anyone know more?
Also, I need a picture to see an example for replacing an irregular terrain with a rounded obstacle! I draw my imagination in the attached figures. Are they true?
I measure the power of RF ambient noise (radio noise) that is captured by the antenna with a sensitive receiver that has an true RMS detector. If the power of the ambient noise is only a few dB above the noise floor of the receiver, the measured power will be a combination of the ambient noise and the receiver noise. If the noise floor of the receiver is known, how can I calculate the true power of the ambient noise alone?
We are working on designing a small research UAV system. However we are asking ourselves how to deal with the issues of doppler effect on our RF communications due to the motion of the vehicle.
What are the common techniques to deal with doppler in RF communications?
The sample is a layered system where the lowere layer is a metal that act as an electric ground. The top layer acts as a dielectric. The stripline conductor should be attached on top of the upper layer independent of the sample growth process.
Thanks a lot for any comment!