Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Input Impedance and Gain of a Gigahertz Amplifier Using a DC SQUID in a
  Quarter Wave Resonator   Due to their superior noise performance, SQUIDs are an attractive alternative
to high electron mobility transistors for constructing ultra-low-noise
microwave amplifiers for cryogenic use. We describe the use of a lumped element
SQUID inductively coupled to a quarter wave resonator. The resonator acts as an
impedance transformer and also makes it possible for the first time to
accurately measure the input impedance and intrinsic microwave characteristics
of the SQUID. We present a model for input impedance and gain, compare it to
the measured scattering parameters, and describe how to use the model for the
systematic design of low-noise microwave amplifiers with a wide range of
performance characteristics.

20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an