60-GHz LTCC Antenna Arrays - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 224

Fig. 24 Simulated S parameters of the proposed antenna element with or without the open-ended
SIC. a | S 11 | and | S 22 |, b | S 21 |
Fig. 25 Simulated radiation pattern for the proposed antenna element with the open-ended SIC at
60 GHz. a Port I: horizontal polarization, b Port II: vertical polarization
Feeding Network and GCPW-SL Transition
A compact multilayer SL feeding network consisted of two 1-to-32 power dividers is
employed to achieve dual polarization characteristic of the antenna array, as Fig. 18
shows. One 1-to-32 power divider located at M2 layer is used to excite the horizontal
polarization and connected to Port H. The distance between the Port H feeding
network and the bottom ground (M1 layer) is 0.1 mm. The other 1-to-32 power
divider located at M3 layer is used to excite the vertical polarization and connected
to Port V. The distance between the Port V feeding network and the bottom ground
(M1 layer) is 0.6 mm.
To make the loss from the transmission line of the feeding network, as far as
possible to shorten the transmission line length is considered, a low-loss cross-over
structure is used in the Port V feeding network to shorten the transmission line length