List of things we are going to look forward under Antenna Array
List of contents
- Two-element, N-element linear array
- Uniform (amplitude & Spacing) arrays
- Broadside and End-fire array
- Uniform spacing, Non-uniform amplitude arrays
- Binomial array, Dolph-Tschebyscheff array
- Planar Array, Circular Array, Log Periodic Antenna, Yagi-Uda Antenna Array
- Basic Wire Antenna- Infinitesimal Antenna (l<<l)
- Few points about Single Element an Antenna
- Radiation Pattern is relatively wide.
- Provides low values of directivity (gain)
- Need of Long Dist. Comm. (or many Applications):
- Very directive antennas (Very High Gains)
How to fulfill the need?
- Increasing the size of the Antenna
- electrical and geometrical
- How to increase the size of an Antenna
- Two ways:
- 1.Enlarge the dimension of single element
- 2.Enlarge the dimension of the antenna without increasing the element size, by forming an assembly of radiating elements, i.e. An array.
- Two ways:
- The antenna formed by multi elements is referred as an ARRAY
- Elements: Mostly Identical (for simple, convenient & practical)
- Forms (Wires, Apertures, etc)
Field of an Array
- The total field of the array is a vector addition of fields of individual elemens.
- Constructive Interference of the field (Add) of individual elements.
- Destructive Interference of the field (Cancel) of individual elements.
Five Controls of an Array (Identical Elements)
- Geometrical Configuration of the overall array.
- Linear, Circular, Rectangular, Spherical
- Relative Displacement between the elements
- The excitation amplitude of the individual element
- The excitation Phase of the individual elements
- The relative pattern of the individual elements
FIELD EQUATIONS OF SINGLE ELEMENT
TWO ELEMENT ARRAY
“ The product of the field of a single element at a selected reference point (usually origin) and the Array Factor of that array is called as the concept of Pattern Multiplication”
N-Element Linear Array: Uniform Amplitude and Spacing