Planar Sub-Millimeter-Wave Array Antenna with Enhanced Gain and Reduced Sidelobes for 5G Broadcast Applications

In this paper, a compact, broadband, planar array

antenna with omnidirectional radiation in horizontal plane is

proposed for the 26 GHz fifth-generation (5G) broadcast

applications. The antenna element is composed of two dipoles and

a substrate integrated cavity (SIC) as the power splitter. The two

dipoles are placed side-by-side at both sides of the SIC and they

are compensated with each other to form an omni-directional

pattern in horizontal plane. By properly combing the resonant

frequencies of the dipoles and the SIC, a wide impedance

bandwidth from 24 to 29.5 GHz is achieved. To realize a large

array while reducing the complexity, loss and size of the feeding

network, a novel dual-port structure combined with radiation and

power splitting functions is proposed for the 1st time. The

amplitude and phase on each element of the array can be tuned,

and therefore, the grating lobes level can be significantly reduced.

Based on the dual-port structure, an 8-element array with an

enhanced gain of over 12 dBi is designed and prototyped. The

proposed antenna also features low profile, low weight and low

cost, which is desirable for 5G commercial applications. Measured

results agree well with the simulations, showing that the proposed

high-gain array antenna has a broad bandwidth, omni-directional

pattern in horizontal plane, and low side-lobes.