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2.4 GHz helical antenna radiation pattern (NEC simulation) The Numerical Electromagnetics Code, or NEC, is a popular antenna modeling computer program for wire and surface antennas. It was originally written in FORTRAN during the 1970s by Gerald Burke and Andrew Poggio of the Lawrence Livermore National Laboratory. The code was made publicly ...
A competing third criterion is the number and bandwidth of the frequenc(y/ies) that a single antenna intercepts or emits. A fourth design goal is to make the antenna directional: To project or intercept radio waves from only one vertical and / or horizontal direction as exclusively as possible.
Most domestic microwave ovens operate by emitting a very high power signal in the 2.4 GHz band. Older devices have poor shielding, [10] and often emit a very "dirty" signal over the entire 2.4 GHz band. [a] This can cause considerable difficulties to Wi-Fi and video [12] transmission, resulting in reduced range or complete blocking of the signal.
Mobile services are operated in the 2.3 GHz to 2.6 GHz range, specifically between the 2300 - 2400 MHz band and the 2500 - 2690 MHz band. Spectrum in the 3.55 - 3.7 GHz band has been auctioned off in the United States to be used for CBRS services and spectrum between 3.45 - 3.55 GHz and 3.7 - 3.98 GHz has been auctioned off by the FCC for 5G although this spectrum is referred to as C Band by ...
The invention of the rectenna in the 1960s made long distance wireless power transmission feasible. The rectenna was invented in 1964 and patented in 1969 [2] by US electrical engineer William C. Brown, who demonstrated it with a model helicopter powered by microwaves transmitted from the ground, received by an attached rectenna. [3]
Slotted array UHF television broadcasting antenna. As shown by H. G. Booker in 1946, from Babinet's principle in optics a slot in a metal plate or waveguide has the same radiation pattern as a driven rod antenna whose rod is the same shape as the slot, with the exception that the electric field and magnetic field directions are interchanged; the antenna is a magnetic dipole instead of an ...
Before the rubber ducky, antennas on portable radios usually consisted of quarter-wave whip antennas, rods whose length was one-quarter of the wavelength of the radio waves used. [1] In the VHF range where they were used, these antennas were 0.6 or 0.9 m (2 or 3 feet) long, making them cumbersome. They were often made of telescoping tubes that ...
A transmitarray antenna (or just transmitarray or called as layered lens antenna [2]) is a phase-shifting surface (PSS), a structure capable of focusing electromagnetic radiation from a source antenna to produce a high-gain beam. [3] Transmitarrays consist of an array of unit cells placed above a source (feeding) antenna. [4]