60-GHz LTCC Antenna Arrays - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 228

Fig. 31 Photograph of the
proposed fabricated
dual-polarized antenna array
with open-end SICs

The measured and simulated S parameters of the proposed antenna array are
illustrated in Fig. 32 . The simulated 10-dB impedance bandwidths are ∼ 19.1 %

with respect to 60.25 GHz from 54.5 to 66 GHz for Port H, and 24.4 % with

respect to 61.5 GHz from 54 to 69 GHz for Port V, respectively. The measured
reflection coefficients of antenna array is slightly worse than the simulated values.
The discrepancy could come from the LTCC fabrication tolerance and substrate
shrink, the inaccuracy of the dielectric permittivity, and even from the touching
position of the Ground-Signal-Ground (GSG) probe influence.
Figure 33 shows the measured and simulated input ports isolation of the proposed
dual-polarized antenna array. It can be seen that, the simulated | S 21 | of the antenna
array is less than

∼

− 25 dB from 58.5 to 65 GHz. Whereas, the measured isolation

| S 21 | is below 20 dB over the frequency range from 58.5 to 65 GHz.

The measured gain of the proposed antenna array for Port H and Port V are plotted
in Fig. 34 , and compared with the simulated results. Considering the metal chuck and
the different calibrations needed for this setup (standard horn antenna, waveguide

−

Fig. 32 Measured and simulated S parameters of the antenna array, a Port H (| S 11 |), b Port V (| S 22 |)