Electrically controlled phase shifters use
varactor diodes or nonlinear dielectrics.
The series portion is designed with two interdigital capacitors and two
varactor diodes [D.sub.S1] and [D.sub.S2] connected in parallel.
A 5-5.47 GHz LC-VCO using
varactor configuration in 0.18 um CMOS, in Proceedings of the 2nd International Conference on Signal Processing and Integrated Networks (SPIN 2015), 19-20 February 2015, Noida, India, 87-89.
The tunnel diodes used in our prototypes are various Germanium models ranging from General Electric 1N3713 to 1N3717 [26] whereas the
varactor diodes are the low-capacitance and hi-Q type Silicon Abrupt Junction Tuning Diodes (SMV1405 series, Skyworks, Inc.).
By switching the
varactor diodes that load the dipoles of the FSS, the reflection coefficient is modulated.
To implement the high-speed mode using digital three- point modulation, a dual-varactor circuit technology was developed that, when in high-speed mode, increases the variation in the
varactor's capacitance at the VCO, which takes the high-frequency modulated signal as input.
- To implement the high-speed mode using digital three-point modulation, a dual-varactor circuit technology was developed that, when in high-speed mode, increases the variation in the
varactor's(3) capacitance at the VCO(4), which takes the high-frequency modulated signal as input.
This model is chosen because of the range of capacitance effect of the
varactor which is sufficient to tune the filter from 2 GHz to a desired minimum center frequency of 1 GHz (using (15), [C.sub.r] is approximately equal to 2 pF).
The probe fed microstrip antenna design consists of a ground plane, an air gap of 60 mils to accommodate the
varactor diodes, a single layer of Rogers RO 4232 substrate and the patch on top.
In [5-9], tunable one stop-band filters are proposed based on
varactor loaded split ring resonators, RFMEMS metamaterials and DGS respectively.
In addition, the
varactor contribution is represented by a bias-dependent capacitance [C.sub.ds].
Tuning LC parameters at a fixed frequency can be obtained by incorporating
varactor diodes [9] and/or tunable inductor chips [10] along the structure.