Design of compact stop-band extended microstrip low-pass filters by employing mutual-coupled square-shaped defected ground structures

A new technique to reduce the size, improve the rejection in the stop-band of a low-pass filter using modified defected ground structure (DGS) is proposed. An equivalent circuit model is used to study the DGS characteristics. The parameters are extracted by using a simple circuit analysis method. Several comparisons between the EM-simulations and the circuit simulations of the new structure are demonstrated to show the validity of the proposed equivalent circuit model. We demonstrated that the filter can provide a sharp transition domain and a wide rejection in stop-band. To further verify the new technique, a filter employing the new deformed DGS is fabricated and measured. The agreement between the simulation and the measured results confirms the effectiveness of the proposed concept. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1107–1111, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23273Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58033/1/23273_ftp.pd

Parallel Computing Applied To Compensate The Effect Of Amplifier Bandwidth In The Design Of Switched Capacitor Networks

A method is described for the extraction of capacitor values for switched capacitor (SC) networks which compensate for the effect of finite amplifier bandwidth in the design of SC networks using optimization. The finite bandwidths of the amplifier distort the response of the network from the required response. It is shown that by readjusting the poles and zeros of the transfer function, the required response can be accurately restored. The values of capacitances are extracted by running a number of parallel local optimizations, each starting from different random initial conditions, on a network of transputers. This method removes the possibility of an optimization being trapped in a local minimum and ensures the stability of the design network