Typical sector antennas have 60, 90, or 120 degree beamwidths.Ĭantenna - a the other end of the "spectrum" from commercial antennas (some pun intended), the cantenna is a homemade directional waveguide antenna, made out of an open-ended metal can. They are typically used in cellular base station towers. Sector antennas are another type of semi-directional antennas that have a fan-shaped (sector-shaped) radiation pattern, somewhat wide in the horizontal plane, and relatively narrow in the vertical direction.
Reflector grid/dish antennas - highly directional with typical gain up to 24dBi, with parabolic reflector that is either a metal grid, or sometimes similar to satellite dish reflector.
#Patch antenna wifi diy Patch#
Patch antennas can have multiple polarities/frequencies built onto the same antenna. Patch/Panel antennas - flat, square, or rectangle antennas with typical gain of 10-20dBi.
#Patch antenna wifi diy tv#
Used as rooftop TV antennas, and, more recently in ptp wifi applications. Yagi antennas - consists of multiple parallel dipole elements in a line, typical directional gain of up to about 17dBi. Some of the most common types of directional antennas, and their uses are listed below: An analogy for the radiation pattern would be how a flashlight directs light in one single direction. Directional antennas offer high focus of the wireless signal in a specific direction, at the expense of very low gain in other directions, resulting in a limited coverage area. Typical directional antenna radiation pattern. If aiming at it with a directional antenna, it is important to match the polarity for the best possible signal. A typical "rubber duck" antenna, as found on most residential routers/access points with external antennas, has vertical polarity. Omni-directional antennas have a 360 degree donut shaped radiation pattern to provide the widest possible signal coverage perpendicular to the antenna (in the horizontal plane if the antenna is pointed vertically). Generally, gain in one direction is offset by less coverage in other directions. Higher gain antennas offer longer range in the horizontal pane (perpendicular to the antenna), at the expense of a much flatter coverage area. This is a typical omni-directional antenna pattern. The most common type of WiFi antenna is a "base" omni-directional antenna, typically used in residential NAT routers and access points. The antennas used for wireless networking (or any other radio transmission) can be classified as either omni-directional, or directional, depending on their gain pattern. It does little good to have a router/access point with a strong transmitted signal if wireless clients don't have equivalent range to reach it back. If you replace the antenna(s) with higher gain ones, however, you amplify both the transmitted and received signals on your router, which is necessary to establish a two-way connection. So, while your new high power router can send packets further, and your clients may be able to "see" it, they still can't reach it to acknowledge any packets, and unable to establish a connection. If no such acknowledgement is received, the sender will retry until a timeout is reached and the connection is dropped. This is due to the fact that 802.11 standards use "positive acknowledgement" protocol, where each data packet transmitted by your router needs to be acknowledged by the client (via a reply to the router). Simply replacing a wireless router with one that has higher TX power usually does not help increase wireless coverage. Increasing antenna gain is better for wireless networks than increasing TX (transmit) power. So why is a higher gain antenna useful, then ? Consider this: A higher gain omni-directional antenna (most common type on routers/access points), for example, will simply provide higher gain in the horizontal plane, at the expense of lower gain in the vertical plane. It is important to understand that higher gain antennas simply change the shape of the radiation pattern, making it flatter, or more directional at the expense of gain in other directions. We will focus on covering most common antenna types for higher range wireless data communications (in the 900MHz, 2.4GHz and 5GHz bands). Still, it is important to understand the basic concepts to help you in choosing the right equipment for maximum coverage and minimal interference. This is not always feasible, or even necessary with built-in arrays and non-removable, or internal antennas on some residential equipment. Installing an external omni-directional, or directional antenna with some good gain, at a proper location can make a huge difference in reception, wireless coverage area and wireless speed. One of the most important considerations for any radio communication, including 802.11 Wi-Fi networks, is the antenna, or "aerial".
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