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24

Digikey sources their parts from the manufacturers and adds a retail mark up. The alibaba seller takes remnants from someone's production run (or possibly salvaged parts, or if you're unlucky counterfeit or reject parts) they don't pay full price. Usually it's remnants, someone makes 10000 products and has 500 parts on the last 3500 part roll left over and ...


21

Dielectric resonator antennas, commonly referred to as chip, work by creating a standing wave of electrical field of a given frequency. Technically, it is a cavity resonator where the cavity between conductive surfaces is filled by the ceramic core. The actual oscillation mode will be defined by the geometry of the antenna. In the simplest case, the geometry ...


19

There seems to be a remarkable lack of relevant on-web material. Maybe just hiding. This looks highly apposite Design of New Multi Standard Patch Antenna GSM/PCS/UMTS/HIPERLAN for Mobile Cellular Phones with an interesting appearance And tri-band !!! GSM Dipole antenna - very informative Designing a GSM dipole antenna Commercial product. LOOKS simple....


18

To discuss the manufacturing and structure of chip antennas, consider first some images of antennas with obvious metalization patterns: From Mitsubishi Materials, the AM11DP-ST01*: There's a whole line of these antennas with visible external metalization for wide or narrow application operation. The smallest, AM03DG-ST01, gets down to about 3.2mm long. ...


14

It seems to be a patch antenna array, analogous (among many images you could find googling around) to this one: Patch antenna arrays are a special kind of microstrip antennas. You can find many details about them in this article. A relevant excerpt: PLANAR MICROSTRIP ARRAYS Planar microstrip arrays are used to form a pencil beam and array elements ...


10

An antenna converts a low impedance transmission line (from the chip or also via a coax or stripline) to a high impedance at the end of the antenna. The high impedance is to suit the impedance of free space (377 or 120\$\pi\$ ohms). An antenna does this gently and in doing so creates a standing wave along its length in order to allow the current to gently ...


9

First of all is it possible to create 10 GHz wave on a PCB? Any clue on how to do something like, regarding the circuitry? If by "creating" you mean propagating and/or radiating, the answer is yes. However, you need to use specific board substrates like Rogers 4000 series, with low losses and controlled dielectric constant up to that frequency. Your ...


9

I would say that they are probably counterfeit,this is a well known problem when buying from china, you cant be sure that they are original unless you are buying from a trusted chinese supplier. Most of the time they work alright if you are not pushing them to the spec limits,here are some links that can help you through this problem of chinese counterfeit ...


8

The basic organization of Eagle files is that all libraries used end up in the final .brd and .sch file. There exists a User Language Program (ULP) that can export all the parts contained in a schematic, including the package footprint called exp-project-lbr.ulp. This file should be included with your Eagle installation. (thanks to this YouTube video for ...


8

QuickField Student edition - 2D finite element package - Windows Trace Analyzer - Transmission line parameter calculator for PCB's - Win/Mac/Linux SATE - Static Field Analysis Toolkit - 2D E-Field - Windows Radia - 3D Static magnetic fields - Mathematica plugin PDN Mesh - 2D field problems (Poisson and Helmholtz Equations). - Windows OpenEMS - open ...


8

all lines are single ended (like UART, SPI, I²C, etc.) and may have transition times of 1~3 ns. This is where you went wrong. I2C and UART run at a few MHz at the fastest. SPI can be run at maybe 10 MHz. There is no need for transition times as fast as 3 ns. You will save yourself a lot of grief by slowing these down. The easiest way to do it is to add ...


8

Neither will work. If you build a metal case with a narrow opening, you'll have an even wider beam; the smaller the aperture, the larger the beam. It's practically impossible in this form factor to controlledly cut off the existing antenna, and still have something to attach an external antenna to. But even so: at 2.4 GHz, the ground you mention will work ...


6

Here's how it works but a couple of factoids first: - According to this source, the most common frequency of transmission is 437 MHz Antenna gain\$^1\$ for a 1m dish is about \$0.5\cdot\dfrac{(\pi D)^2}{\lambda^2}\$ and at 437 MHz \$\lambda\$ is about 0.69 metres and gain will be about 10 and in dBs this also is 10dB Link loss from satellite to earth is: - ...


6

Yes, the component you show is clearly a coil, which is almost certainly there to provide inductance. The impedance of a antenna varies widely with frequency and even relatively small geometry changes. Ideally a antenna looks resistive at the desired frequency, but it is often impossible to make the bare antenna look resistive in a size-constrained device. ...


6

How about this document about antenna design for the PN512? The rectangular antenna on page 47 looks like it will meet your needs. Texas instruments also makes some fairly decent HF antenna design guides. I've fabricated some of these rectangular antennas for 13.56MHz NFC before (the ones specified by TI), they're fairly simple and work well as can be ...


6

Edit: I was wrong, it can. Here's a picture of a similar antenna: And here's it's radiation pattern: The radiation pattern is a polar plot of the relative gain of the antenna at each angle. As Andy aka and mouseas pointed out, this plot is in dBi, which is a logarithmic unit (it's dB relative to an ideal isotropic antenna). That means that in some ...


6

Yes it does, in contrary to other answers. It's not an isotropic antenna and will have more gain in one direction than another. This affects transmission distance. Using the example shown in aloishis89's answer there is clearly a 10dB difference in antenna gain in one direction compared to another. Using the Friis Free-space formula for link loss: - Link ...


6

All else equal, the differential traces will radiate less. This is because their opposing electric fields cancel for distances "far" away, with "far" being relative to the spacing of the traces. Less radiation also means less opportunity to pick up or contribute noise to or from other components near the feedline, which may or may not be a concern for you. ...


6

These things are all PIFA (planar inverted F) antennas. They all perform exactly the same, though they have to be carefully designed to fit into the enclosure and have the correct resonances. The basic idea is to add cuts in such a way that the path the current takes through the antenna cause it to resonate at a lower frequency than the overall size would ...


6

It's not that the plane will block transmission in one direction, but that it will absorb much of the power you put into the antenna, and also greatly change the antenna characteristics. The plane is in the near field, which means the antenna can "see" it. It will cause the electrical properties of the antenna to be quite different than when there is no ...


6

As someone who has been in the electronics sales and distribution world for a couple years now, I can say from experience that the majority of mobile handset chipset suppliers such as Qualcomm have their documentation on a secure portal and will only grant access to either top tier customers or other tier 1 customers that sign NDAs where the suppliers feel ...


6

is whether "fingers" A, B, D and E should be removed or perhaps they contribute to reducing crosstalk between the tracks. They should be removed because as is they do not really help and quite possibly, will make things worse. Your concern appear to be crosstalk. So lets talk about that for a second. Crosstalk is when the feilds (either electric or ...


5

Since that pour is connected to ground, I would not remove it. First, because there's no currents flowing in that area, there's no reason for it to radiate. Second, because rather than acting as an antenna, it will act as a (extra) place for fields from the nearby traces to go, so they don't become antennas. Which of course implies that small currents will ...


5

The big question is: what distance do you want to cover? The data sheet of the transmitter quotes a maximum range of 50 metres [about 150 ft]. Will you use that, or will the receiver be closer? Any oscillating signal will radiate: the whole point of the USA's FCC is to limit the amount of annoying [or dangerous] EM radiation coming from devices. Depending ...


5

From this document: One big advantage for the short whip is that it can be a trace on a PCB, with a chip inductor used to tune out the capacitive reactance of the antenna. If the trace runs parallel to ground, the real part of the antenna impedance will be approximately 10 ohms. In a hand-held unit, the impedance will be raised substantially ...


5

The easy way: Keep your design as-is. The wavelength at 1800 MHz is 167 mm. Your track length is 10 mm. This is less than 1/10 wavelength so you can probably get away with not worrying too much about controlled impedance on this line. Certainly the few mm of necked-down trace at the pad end of your track are not going to be a big problem. The hard way: ...


5

Additional specifications as clarified by "tman" Signal is not expected between 75deg and 90 deg and also between 0deg and -90deg elevation, and rejection in these sectors is not explicitly required. An omni-directional antenna is an acceptable solution. The antenna is to be used indoors in a fixed installation -- inside a home at about ceiling height. This ...


5

Your requirements will never be met. A dish antenna is the best for providing focus and if you looked at voyager II, it used a 3.7 metre dish at about 3 GHz. This would give a 3dB half-beam-width of about 0.91 degrees. I'm using the example of Voyager II because they would not ship something to the planets that had not been thought about (o-rings excluded ...


5

Regular 802.11 Wifi networks use something called a beacon frame to transmit all of their "housekeeping" information. This includes info like the SSID, the current time, and the supported data rates. It gets transmitted every 102 ms. WiFi receivers can only detect nearby networks by watching for these beacon frames. There is no difference between receiving ...


5

Apart from EMI issues, I have a hard time believing that this will work at all. Is there a reference design available for something similar? From what I would guess (I'm not an antenna specialist at all): Multiple drivers for one antenna No matching network (at least none which could be used if required) Your antenna line doesn't have a solid reference but ...


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