| dc.description.abstract | This paper utilizes the WIN 100-nm GaAs pHEMT process to
design low-noise ampli ers intended for the millimeter-wave frequency
bands in fth-generation mobile communication. Chapter 2 presents
the design of a common-source single-stage LNA structure for the 48
GHz band frequency range. Chapter 3 focuses on the design of two
cascaded single-stage LNAs for the 48-band frequency range. These de
signs involve input and output matching using transmission line parallel
matching in one case and capacitor parallel transmission line matching
in the other.
In Chapter 2, we designed an LNA for the 48-GHz band. The
matching network employs transmission line shunt elements, with in
band and out-of-band bypasses at the input and output to enhance
circuit stability.For a device size of 2×25 µm, the small-signal measure
ment results show a gain greater than 6.7 dB, input return loss greater
than 4.6 dB, output return loss greater than 28 dB, NF of 1.96 dB at
48 GHz, and 1 dB compression point of −2.5 dBm. The measured and
simulated frequency performance align well.
In Chapter 3, we designed a cascaded low-noise ampli er for the 48
GHz band with two matching methods: the rst employs transmission
line parallel matching, and the second uses capacitor-parallel transmis
sion line matching. Both circuits utilize in-band bypass and out-of-band
bypass at the input and output to enhance circuit stability. Circuit di
agram 3.1 utilizes transmission line parallel matching. The small-signal
III
measurement results show a gain greater than 12.9 dB and a noise gure
of 2.67 dB at 48 GHz, with the gain tending towards lower frequencies.
After debugging simulation, the circuit maintains consistent trends in
gain, input, and output return loss at the design center frequency. The
revised gain after debugging simulation is 12.7 dB, closely matching the
measured 12.9 dB, with a 1 dB compression point of −10 dBm at 44
GHz.
Circuit diagram 3.2 employs capacitor-parallel transmission line
matching. The small-signal measurement results show a gain greater
than 12.5 dB and a noise gure of 2.68 dB at 48 GHz, with the gain sim
ilarly trending towards lower frequencies. After debugging simulation,
the circuit maintains consistent trends in gain at the design center fre
quency. The revised gain after debugging simulation is 12.3 dB, closely
matching the measured 12.5 dB, with a 1 dB compression point of −18
dBm at 44 GHz | en_US |