Biomedical Engineering Reference
In-Depth Information
Fig. 1
The spectrum alloca-
tion around the 60-GHz band
for some countries and
regions [
3
-
5
]
The IEEE 802.15.3c task group was formed to standardize 60-GHz radios in March
2005, and the IEEE 802.15.3c standard was published in September 2009 to define
available and unlicensed frequencies band from 57 to 66 GHz as the 60-GHz band
radios applications [
2
]. The standard divides nearly 9 GHz frequency bandwidth into
four 2.16-GHz channels. The Nyquist bandwidth of the standard is 1.632 GHz with a
guard bandwidth of 264 MHz on each side to limit spectral leakage. The standard also
enforces basic transmission modes: common mode, single-carrier (SC) mode and
orthogonal frequency division multiplexing (OFDM) mode. Significant progress has
been made in regulations, standards, and solutions. According to the actual situation
of countries and regions, different countries and regions have established the 60-GHz
regulations for unlicensed utilization, as is shown in Fig.
1
. Japan first issued the
60-GHz regulation for unlicensed band from 59 to 66 GHz in the year 2000. The
maximum allowable antenna gain of 47 dBi and maximum transmission bandwidth
of 2.5 GHz. In 2004, the United States allocated 7 GHz from 57 to 64 GHz for
unlicensed use and specified a total maximum transmit power of 500 mW for an
emission bandwidth greater than 100 MHz. The 60-GHz regulation in Australia
is a narrower 3.5 GHz bandwidth from 59.4 to 62.9 GHz than 7 GHz bandwidth
in Japan and USA. The maximum transmit power is limited to 10 mW. A wider
9 GHz bandwidth from 57 to 66 GHz is recommended in Europe. The maximum
transmit power of 20 mW, maximum allowable antenna gain of 37 dBi, and minimum
transmission bandwidth of 500 MHz are established. Therefore, antennas with wide
operating bandwidth to cover more than 9 GHz of the whole 60-GHz bandwidth for
different countries and regions applications are desired.
The atmospheric absorption property of sub-terahertz radio spectrum is shown in
the Fig.
2
. The 60-GHz band is located at the peak point of the oxygen absorption
with high attenuation and large propagation loss. The dramatic attenuation at the
60-GHz band is suitable for “whisper radio” short-range wireless communication,
where weak signals do not propagate more than a few meters before dropping below
the thermal noise level. For 60-GHz wireless communications, the link budget is
constrained due to low transmit power (10 mW), large propagation loss (68 dB at
1 m), and high data rate (
≥
1.5 Gb/s). Assuming the 10-mW value for the average
Search WWH ::
Custom Search