Compact
dual-polarization antenna for a mobile device
Compact Antenna
Disclosed Anonymously
Microstrip antennas have been used in wireless
communications for many years due to their low profile, lightweight, low-cost
characteristics and compatibility with mounting structures. Recently, studies
on microstrip antennas have focused on frequency reuse and polarization
diversity of the two-orthogonal polarizations to double the capacity of communication
systems and reduce the multi-path fading of received signals in land– based
mobile-communications. Moreover, dual-frequency microstrip antenna arrays, often
realized through a multiplayer architecture, have gained considerable interest.
However, there have been some inherent challenges in the design and architecture
of dual-polarized dual-frequency band microstrip antenna arrays.
Conventionally, a dual-polarized microstrip antenna is
realized by feeding a patch at the two orthogonal edges. This feeding approach
requires two feeding networks for two individual polarization components,
respectively. But, it is very difficult to find enough space to accommodate two
sets of feeding networks if a dual-polarized array is employed within a limited
allowable space, such as in a handset device. Hence, strong mode coupling and
high cross polarization will occur. The problem will become more severe if one
wants to integrate active and passive circuits into the feed-networks. Furthermore,
if a dual-frequency operation for the above dual-feed dual-polarized array is
realized by multilayered architecture, the size and complexity of the array
will be further increased. To overcome the above problems, it is important to
create novel miniaturized dual polarized dual-frequency arrays. Three new dual
polarization, planar antenna designs that satisfy these requirements are given
below.
1. Compact Single-Fed Dual-Polarized
Dual-Frequency Band Microstrip
Antenna Array
A novel single-fed dual-polarized dual-frequency band
microstrip antenna array is proposed. It consists of two stacked sub-arrays
with different element sizes. Instead of introducing two feedings and
complicated feeding networks, the dual polarized dual-frequency band array uses
only one feeding, which significantly reduces the complexity of design and
fabrication, as well as cross polarization levels, and also effectively avoids
feeding couples in the two feeding networks. With the above attractive
features, the proposed structure provides a unique inexpensive solution for
high performance dual-polarized dual-band antennas for wireless communications.
The single-fed dual-polarized dual-frequency microstrip
antenna array structure
is shown in Fig.1. The antenna
consists of two sub-arrays, and they are etched on the
opposite two sides of a PCB. The
bottom sub-array is over a common ground plane.
Each sub-array has four id...
