At a frequency of 2.45 GHz WiFi signal wavelength is 122 mm. Polarization is vertical. The network diagram is curious biquads, around a curved copper pipe of diameter 10 cm. It turns out that a diagram similar antenna is distorted and stretched along the azimuth. No MMANA models to see what exactly it turns out, but fans argue that such a course is not the best (the review and it). Horn antennas are suitable for high frequencies and for low are too cumbersome. Is it possible to make the antenna to the router's own hands as a megaphone. In exceptional cases (an imitation of the voice of the lake ducks), certainly, yes.
Antennas to router
Few think about the physical meaning of the antenna. The residents answer, the antenna is required to amplify the signal, but it is not a passive reinforcing device. It collects a large area signal and delivers a small where the receiver cable. It makes all the antennas without exception. What can assemble a vibrator? Suffice it to recall that the wave vibrator (length of wire equal to the wavelength) better half-wave having an advantage over the quarter-wave (equal to a quarter wavelength). The longer the dipole, the more effective. In this respect certain proportion. This wave is dictated by the laws of nature.
It is known that an opera singer, taking note of the high divides crystal glass. How it's done. singing master strikes lightly on the device and listen to what the note will pour out of dishes. This object resonance frequency. Taking the same note-modulated voice, the singer strikes a chord capacity. Fluctuations accumulate, amplify, not fade. As a result, the glass shatters. Exactly the same happens in the antenna. Collects and transmits waves is resonant. This fundamental frequency and harmonics (multiplied by two, four, and so forth. frequency). Homemade antenna for the router will help weed out the unnecessary. The signal will be concentrated in the right place.
It is important to bring to the antenna cable correctly. Reception waves and harmonics allow manufacture harmonic antenna receiving a frequency whose half wave are multiples of the dimensions of the device.
For example, frequency, correlated as 1: 2: 4: 6, etc. Correctly Summing up the line will catch multiple waves. If you break the rules, the device will not work. Here's how to do:
- It depicts schematically vibrator (straight line), which schematically represent current distribution laws and voltages for all wavelengths.
- If you attach the wire at the antinode of stress, get washing voltage.
- If you attach the wire at the antinode of all currents turn-current washing.
So are made harmonic antenna. For the manufacture of the kind, for example, for a frequency of 3.7 MHz (HF range) needed piece of wire 80 meters. It is clear that such a scenario can not be tolerated. Therefore constantly searching for new designs. Recently published description ferromagnetic antenna design process for a range of 3.7 - 7 MHz, fits in the fist. We do not claim that replaces him 80 meters of copper, but the positive effect of it, researchers observed that used in radio receivers.
Horn antennas for wireless router
The delight amplifying horn antenna for the router. Easy to design. Here's the theory:
- horn antenna consists of the socket and the feed waveguide;
- components agreed upon, or the signal passes through the joint space;
- horn made of different shapes, "reflector" determines the type of antenna:
- pyramidal (trimmed pyramid);
- pie, sectorial (sector of the waveguide, the bottom and the ceiling parallel to each other, the sidewalls diverge);
- conical (truncated cone);
- hybrid (trumpet shape can hardly be called already coined the word, those who judged the satellite converters, sign horn with steps).
If the satellite communications at frequencies above 5 GHz apply horns, then suitable for WiFi. How to make antenna for the router. The horns are a class of microwave devices. The antenna is made of silver-plated steel inside. This improves conditions conductivity allow the wave to move freely inside the walls give firmness. In practice, for the glazed loggias suitable cardboard, pasted inside the foil. The foil, as is known, made from aluminum, copper has better qualities. Some collect horn antennas from PCB. Then the surface is polished, for example, an eraser, and varnished. Portal horn antenna dielectric seal, plastic, foam and the like. D.
Important! Without foil horn will not work for obvious reasons. The insulator may not reflect electromagnetic radiation.
The joints in the case of textolite soldered, glued cardboard. Probably better to take the plywood, for correct geometry is important for the antenna. A veneer sheet holds its shape better. Inside required to glue at the seams, and outside primer coat, preventing the penetration of moisture inside. Next, painted and hung anywhere. If desired, the upper part may attach bird feeder. Inside okleyte structure foil smoothly (work antenna pasting will not affect the evenness) possible. Offer to do a pyramidal horn is easier, and provide an acceptable pattern and elevation in case strangers want to get into our network.
The bottom of the feed waveguide bottom punches pin spaced from the rear wall by a quarter wavelength and the length of half a wavelength. According to the formula of physics we find wavelength: 299792458/2430000000 = 123 mm. Is the wavelength in free space. The waveguide is critical wave may not work below it. The value is equal to twice the long side of the waveguide. Calculator follow the advice and take wall of 90 x 60 mm. critical wavelength will be 180 mm. Inside the waveguide wave is moving at an angle. Consequently, the wavelength increases, equal to the quotient of the wavelength in free space dividing by the cosine of the angle of movement inside.
The difficulty is in finding the angle. To calculate the derived special formulas, their readers will find yourself, as we use the results. Initially, the calculator is prompted to specify the size of the horn. Here are the correct values. Following the procedure find hand parallelepiped including an opening horn (without feeding waveguide). It turns out:
- Length P - 60 cm.
- H Width - 25 cm.
- E Height - 10 cm.
Dimensions external portal found, and internal equal input into the waveguide. This will determine the geometry of the four walls. Click on Compute and get ready template. Note the graph Aperture Quality (aperture quality). It should be 1/8 wavelength smaller number (in this case 15 mm). From initial site data came out a quarter, but the author is not sure of the correctness. First glue the layout is not hard, but try first on the ground. Note that already felt the wavelength in the waveguide, the figure was 16.85 cm. Now we understand what to do with the core:
- is spaced from the rear wall of the anechoic waveguide 168.5 / 4 = 42.125 mm;
- waveguide segment has a length of 84 mm;
These are important parameters, they should keep clear. Here the signal is removed from the pin. How to plot setting. The pin protrudes from the bottom to a certain length, is a quarter wavelength in free space (31 mm). You need to bring the SWR meter and move in different directions, to get the value in the unit. If not for a long time, a little tilt rod to the back wall.
Well, that's ready to external WiFi antenna router. Further conversation will take place on microwave technology.