Questions tagged [microwave]

Questions related to operating on frequencies above 902MHz.

46 questions
Filter by
Sorted by
Tagged with
67 views

Matching antenna at 4.2 GHz using an LC network

I want to match an antenna using an LC matching network: Operation frequency: 4.2 GHz Vacuum wavelength: 7.2 cm Cable: Source Impedance: 50 Ω\ The antenna impedance is unknown, but it is approximately ...
• 101
130 views

Can mobile phones be used to intercept signal in 4-8 GHz frequency range?

I am trying to understand which is the radio frequency band of signals that can be intercepted using a regular mobile phone. In particular, I want to know if the 4-8 GHz frequency range is accessible ...
• 103
186 views

How to calculate phase constant for a coaxial cable?

inner and outer conductor diameters of 1 mm and 5 mm respectively, is filled with a non-magnetic PTFE dielectric having εr = 2.55. frequency = 1 GHz.
• 23
1 vote
397 views

Waveguide size for 2.4 GHz

I'm thinking to make a wave guide that has diameter 1/8 of the wave length. At 2400mhz the full wave length is about 125mm. I have aluminum pipe that is 16mm. So 8*16 = 128mm (very close to 125mm). If ...
220 views

Why measuring Voltage and Current becomes difficult at Microwave frequencies? Why measure Power?

I have been reading some Classic books viz. Techniques of Microwave Measurements - Carol Montgomery, Foundations of Microwave Engineering - Collins, and some other google searches and they all claim ...
• 159
263 views

The Terrestar Genus was able to talk to a GEO satellite in a smartphone-sized package, where's the antenna on this thing?

Background I'm doing some research on a company called ASTS who claims to be able to connect to regular smartphones from a satellite. Initially I wrote off their claims, but after looking into it a ...
1 vote
124 views

I'm working on some research for a project of mine. The project requires the use of millimeter wave radar. I am having a very hard time figuring out what the FCC's regulations on frequencies and ...
• 111
1 vote
47 views

Is it beneficial to boost the transmit power from a transmitter past 2W around 2.4GHz?

I have a ready-made transmitter that outputs 2W of RF power at 2.4GHz carrier frequency (I'm trying to transmit TV using DVB-S2) into the antenna, and I was wondering if it made sense to add a power ...
• 151
209 views

Dielectric coaxial resonator vco circuits topology?

I came across this VCO that uses a dielectric coaxial resonator, I understand how the resonator works, what I don't know is the oscillator topology, Colpitts, Clapp, et. Also I do not see any circuit ...
• 75
263 views

Maximum frequency for discrete components bandpass filter

What is the maximum frequency that can be practical to build a filter with discrete components? I need a band pass filter for 1090Mhz.
• 75
464 views

3D Printed yagi antenna

I'm trying to produce a Yagi antenna for the 2.45 GHz band using a 3D dual extruder printer. The idea is to print the antenna elements using a metal filament and encasing it all in plastic. The ...
• 73
1 vote
152 views

What type of omnidirectional antenna gives the most gain for a frequency of 2.4 GHz?

I have a 2.4 GHz transceiver that outputs 4.5 DBm. I wish to amplify the signal using a 15.5 DBi antenna so that the signal reaches 20 DB, the maximum legal limit. Preferably, the antenna would be of ...
170 views

S Parameters in HFSS

I'm new to HFSS Software and I'm trying to plot Scattering parameters for a dielectric resonator excited by a probe (shown in image). I know that the top cylinder has a higher dielectric than the ...
• 81
346 views

Failing to detect Hydrogen line with 105cm dish

I've seen many examples of roughly 1 metre sized dishes being used w H+ sawbird and an SDR to detect and analyze Hydrogen line signal, and have been trying myself but can't seem to get anything beyond ...
• 51
272 views

Frequency selective surfaces working principle

I've seen that sometimes frequency selective surfaces are used to load a certain impedance to a certain antenna (for instance for input matching purposes). These surfaces act like a filter on the ...
• 279
26 views

Is this result correct ? [ impedance cavity based on emtamaterials using CST Microwave]

In the contexte of my reaserch about antenna conceptions, I'm trying to simulate using CST Microwave a cavity antenna based on metamaterial structure and a slot antenna as a GND,However I got as a ...
838 views

What are the properties of the radiation of a magnetron?

It is commonly known that electromagnetic radiation from an antenna is polarized; the electric field is parallel to the rod and the magnetic component is perpendicular to it. What does the radiation ...
188 views

Why can't we use a simple wire for receiving 2.4 GHz signals?

I wanted to build a small drone of my own as a hobby project. My old drones were broken so I wanted to salvage as much as I could to build a small indoor one. I wanted to use an Arduino, however, I am ...
• 101
960 views

Designing a helical antenna for a dish

I'm interested in a dish antenna with an axial mode helical feed for receiving video. My target frequency is about 1280 MHz or the 1.2/1.3GHz range. I've been able to figure out helical basics, like ...
• 53
346 views

Connecting Directional Antenna To Two Antenna Ports on NIC

I want my n/ac Wi-Fi card to operate in a spatially directional manner. To achieve that I want to use a directional antenna(s). There is a slight complication though, because my Alfa AWUS036ACH ...
• 131
248 views

Circular polarized antenna feed changes as I rotate it?

I had a 100cm prime focus dish laying around and I thought of making a circularly polarized feed for it, since it seemed pretty straightforward from what I've been reading. Helical feeds are supposed ...
• 1,219
127 views

Is it possible to image bones and tissues with radio waves (2.7GHz-5GHz) with a tiny radio frequency source and on one side and a receiver on other side which can image the data through a PC mediated ...
• 103
352 views

2.45GHz: constructing a horn of *thin* steel, what are good ways to join the edges (at least one joint along corner?)

TL/DR: How does someone make a good horn antenna system without using expensively made parts? Welding thin steel for this is not something even pro welders can do (it's a specialty app.) What are DIY ...
• 31
605 views

Is there any 2.4 GHz tuner ICs for SDR receivers?

I have a hackrf one sdr, which i use to transmit test signals. I am using ISM bands, so I can omit transmitting my callsign, checking correct sub band (FM, digital) etc. And one of most interesting ...
• 195
150 views

Wifi inside a rocket

I want to understand, as most rocket uses LAN cable and switches to communicate between stages. Is it possible to replace with WiFi? Although it's will be complex system but one idea to make each ...
375 views

Passive antenna system as a Wi-Fi repeater [duplicate]

I want to extend WiFi signal using a passive repeater between two isolated boxes (have to make both box wireless). Transmitter antenna from box A is placed in the gap between box A and B. In the same ...
76 views

Microwave kiln for glass [closed]

I am building a 1000W microwave kiln for glass jewelry. The internal capacity needs to be around 5 litres. What internal dimensions of the cavity should I avoid, or strive for, to ensure even heating....
• 351
391 views

Applications for 100 GHz band?

I was reading this paper and I found it very interesting and the following question came up, What are the main applications (what is used for) 100 GHz band? I couldn't find any reference on what is ...
• 131
171 views

What are the parameters and necessary features of a Gunn diode oscillator cavity?

There are a ton of old USSR Gunn diodes available on ebay and I'm looking for a cavity that can make use of them. I am willing to machine one myself if necessary, but I'm unable to find any decent ...
• 425
1 vote
173 views

Cell tower identifier antenna isolator cannon

There are several cell towers on the hills around me. Usually I just walk around their base in a circle with one of the many CellID apps to get their ID. Then I can impress my friends, "That's tower ...
• 149
2k views

How to create a simple 1296MHz transmitter?

I have asked this quesion on other sites, but want to try to repeat it here. Also I have asked question about multiplier, and this is a different question. I discovered a 1296MHz beacon in my city ...
• 195
80 views

What is the best approach for measuring return loss of a home-made 3cm horn?

Let's assume I have built a SMA-to-waveguide transition that flares out into a horn antenna. There's no flange between transition and horn, it's made of a single metal sheet. The antenna has tuning ...
127 views

RF inert adhesive for building antennas in the UHF to low GHz region

I want to experiment with different mechanical designs for some Yagi antennas for 440 MHz through perhaps 2.3 GHz. I am looking for some adhesives and/or potting-like materials that would be ...
• 1,035
968 views

The previous question, Packet Radio at 100 miles and specifically, Phil's answer raised an interesting question: In a 50–100 km distance situation where Line-Of-Sight beams aren't an option for ...
• 16.6k
2k views

Why are FM radio waves less susceptible to interference than AM?

When studying modulation of radio waves (or of most electromagnetic waves for that matter) I came across this question: Why are FM waves less susceptible to interference than AM waves? I know that ...
• 133
1 vote
6k views

How to calculate Return loss of 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 ?
• 261
867 views

If I put my mobile phone in my microwave oven and close its door, Should I be able to get incoming calls ? Because, I tried it and I was able to get calls, what does it mean? Does my microwave oven ...
• 327
1 vote
50 views

Picostation Not Accepting AREDN Firmware

Help! I got a PicoStation off of Ebay. When trying to upload the Amateur Radio Emergency Data Network firmware to it, I get Bad firmware update image. How do I get ...
413 views

How far the near-field reactive region extends from the transmitting antenna?

I am doing research on near-field harvesting. In my situation the transmitting antenna is a dipole antenna operating at 2.45 GHz and its length is 14 cm long. I am trying to find how far near-field ...
• 469
410 views

What is this large, flat microwave coaxial connector?

I picked up a random piece of RF hardware at a flea market. I'd like to know what these unusual connectors on it are. The jack is flat on its face except for the gold ring. Inside the gold ring ...
• 24.7k
3k views

How to build the smallest directional antenna (ISM band)?

What kinds of configurations should I try when trying to make the physically smallest 2.4 GHz (ISM band) antenna that is significantly directional front-to-back. "Smallest" meaning in in cm maximum ...
• 13.5k
327 views

why fiber optics replaced microwave [closed]

I was recently reading an article where they mentioned about abandoned microwave towers being replaced by fiber optics. From what I understand microwave technology is better at speeds, is cost ...
• 129
391 views

What is a general procedure for aligning directional antennas?

I want to establish a microwave link (1.2GHz) between two stations using antennas with a directional radiation pattern. The stations have a clear line of sight to each other. Each antenna is attached ...
• 872
405 views

Linksys WRT54G turned in to a brick

I just bought my first WRT54G (V3), and wanted to build a mesh network (Using the Broadband-ham firmware, http://www.broadband-hamnet.org/ , which as I understand is based on OpenWrt). I wasn't paying ...
• 6,278
439 views

Have hams ever used (clusters of) geostationary satellites as passive microwave reflectors?

A number of geostationary satellites are quite large and/or appear in clusters. Moreover, many of them have large reflectors pointing to Earth (e.g. satellite TV sats). Finally, these satellites are ...
• 1,317