Citation Context

...sentially component design problems, which result in system-level simplifications. Examples of such multi-function modules are the integrated antenna-filters [25][26], and tunable/switachable filters =-=[27]-=-[28][29]. 1.1 Thesis Overview In this thesis, the objective is to develop hardware solutions for millimeter-wave beam-steering systems. This includes antenna and filter designs for applications in sim...

Citation Context

...eting these objectives [1], [2]. One of the most critical elements enabled by RF MEMS is the tunable filter, of which there have been several examples. These filters have included both lumped designs =-=[3]-=-–[5] and distributed designs [6]–[9] at frequencies ranging from L-band to millimeter-wave. However, there have been few examples of RF MEMS-enabled filters in the 8 to 18 GHz range where numerous rad...

Citation Context

...rs 2009, 9 8000 5.2. Effects of Residual Stresses Residual stresses are inherently generated during various stages of microfabrication. A general uniaxial residual stress field can be approximated by =-=[21,22]-=-. σ ( z) ≈ σ + σ ( z), res M Gr g ≤ z ≤ g + t o o m where, σM, σGr(z) refer to the mean and gradient (intrinsic) residual stresses generated in the thin film during microfabrication, respectively. Typ...

Citation Context

...ter design at low frequency, the MEMS varactor is used as a lumped element with off-chip inductors. At high frequency, some designs were reported with integrated transmission lines and MEMS capacitors [5, 6]. The transmission lines used for these designs are half wavelength or 180◦, so the filter will be very long at low frequencies. The tuning range is also not very high for these filters, 3.8% and around 14%, respectively. Also, low-pass and band-pass filters integrating capacitive MEMS switches and short inductive transmission lines have been realized for frequencies above 10 GHz [7–9]. In [7], the change in cut-off frequency was obtained by switching different combinations of inductances and capacitances. In [8, 9], the cut-off and center frequencies were tuned by changing the inductance using MEMS switching. However, none of them had the capability of tuning bandwidth. In this paper, we have presented a design of a band-pass filter with combination of low pass filter and high pass filter. The low pass filter was designed using the stepped impedance transmission line. A preliminary design of the low pass filter was presented in [10]. The low-pass filter was integrated with series ...

Citation Context

...ted-element or microwave approaches. With the miniaturization capabilities of MEMS technologies, MEMS variable capacitors have the potential to appear lumped at frequencies into the X-band and beyond =-=[4, 5]-=-. The LIGA (German acronym for Röntgenlithographie, Galvanoformung, Abformung - in English, X-ray lithography, electroforming and moulding) fabrication process appears to be very well suited for RF M...

Citation Context

...itride deposition and RIE etching, (c) sacrificial layer deposition and patterning, (d) sputtering of Au film and patterning, and (e) device release and CO critical point drying. where is the imaginary part of the load impedance, is the character admittance and . The equivalent capacitance of the two stubs can then be calculated as (4) The input and output matching networks are designed following this procedure. Fig. 2 shows the schematics of the two double-stub tuner on a Si substrate. The stubs are implemented with both fixed value MIM capacitors and MEMS capacitive switches. As reported in [8], the implemented MEMS shunt switch behaves as a shunt capacitor between the center conductor of the CPW line and the ground. The capacitance of the switch can be varied to either or by activating the switch. In the input matching network [Fig. 2(a)], the second stub has capacitance of 0.65 pF (provided by MIM capacitor 2) in one configuration and 2.15 pF in the other configuration. Due to the limitation of the down capacitance that a single switch can provide, two MEMS switches are used to provide 1.5 pF when they are pulled down. In the output matching network, both stubs are implemented by ...

Citation Context

... resolution to result in near continuous coverage of the frequency band. The MEMS filter in [46] shows four states (2-bit filter) and a 44% tuning range, with poor frequency resolution. The filter in =-=[47]-=- has two states (1-bit filter) and can switch from 15 to 30 GHz. Other designs have two states and lower tuning range: 28.5% in [48] and 12.8% in [49]. In this chapter, we present a 4-bit digital diff...