These modules can be packaged
together as an array as needed.
Today, semiconductor technology
lets you put one or more modules
on a single semiconductor chip.
A good example of a
commercial product available to
implement phased arrays is the
Anokiwave family of millimeter wave
phased array front-ends. The AWMF-
0139 operates in the 24 to 26 GHz
band allocated to the coming 5G
cellular networks It encapsulates
four modules per IC. Figure 6 shows
how 64 of these chips can be used
to make a 4 x 64 = 256 element
array. Another similar IC is Analog
Phased array antennas can also
be used for multiple input multiple
output (MIMO). MIMO is a technique
that transmits the same data with multiple
antennas over the same path in the same
bandwidth. This does two things.
First, each signal takes a slightly different route to the
receiving antennas. The result is less fading and greater
data reliability. Second, MIMO multiplies the data rate by
a factor that is determined by the number of transmit and
receive antennas. Common configurations are 2 x 2, 4 x 2,
4 x 4, and 8 x 8, where the first number is the number of
transmit antennas and the second number is the number of
A multi-element phased array can be partitioned into
sections making it suitable for some MIMO applications.
For example, the 256-element array could be arranged
to provide four 64-element arrays or sixteen 16-element
arrays. With beam steering capability, the signal path can
be optimized for best performance.
Also, 5G cellular radios operating in the millimeter
wave bands will use MIMO to give gigabit data rates. The
big hurdle is putting a phased array into a smartphone
handset. Initially, two antennas will be used and later will
be increased to four. MIMO is also widely used in Wi-Fi
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Figure 6. The Anokiwave AWMF-0139 IC contains four antenna modules.
These ICs are mounted on the back of the PCB with the patch array on the
88 September/October 2018