A study of the synthesis of 3-port electrical filters with Chebyshev or elliptic response characteristics

The paraunitary property of lossless networks has been exploited to determine relationships for the scattering parameters of 3-port networks (filter pairs) to predispose approximate Chebyshev or elliptic frequency response characteristics. Prior work by Belevitch, Zhu and Chen determined the relationships for Butterworth frequency response characteristics. Networks which demonstrate approximations to Chebyshev and elliptic response characteristics were synthesized from the reflection coefficient of the network using the Darlington method for the second- and third-order cases. Filter pairs which have perfect, non-approximate Chebyshev or elliptic response characteristics were shown not to exist

Design methods for microwave filters and multiplexers

This thesis is concerned with developing synthesis and design procedures for microwave filters and multiplexers. The core of this thesis presents the following topics. 1) New classes of lumped lowpass prototype filters satisfying generalized Chebyshev characteristics have been investigated. Exact synthesis procedures are given using a relatively new technique termed the alternating pole synthesis technique to solve the accuracy problem. The properties of these filters and their practical advantages have been discussed. Tables of element values for commonly used specifications are included. 2) A new design procedure has been developed for bandpass channel multiplexers connected at a common junction. This procedure is for multiplexers having any number of Chebyshev channel filters, with arbitrary degrees, bandwidths and inter-channel spacings. The procedure has been modified to allow the design of multi-octave bandwidth combline channel filter multiplexers. It is shown that this procedure gives very good results for a wide variety of specifications, as demonstrated by the computer analysis of several multiplexers examples and by the experimental results. 3) A compact exact synthesis method is presented for a lumped bandpass prototype filter up to degree 30 and satisfies a generalized Chebyshev response. This prototype has been particularly utilized in designing microwave broadband combline filters. 4) Different forms of realization have been discussed and used in design and construction of different devices. This includes a new technique to realize TEM networks in coaxial structure form having equal diameter coupled circular cylindrical rods between parallel ground planes. Other forms of realization have been discussed ranging from equal diameter posts, direct coupled cavity waveguide filters to microwave integrated circuits using suspended substrate stripline structure. The experimental results are also given. In addition, the fundamentals of lumped circuits and distributed circuits have been briefly reviewed. The approximation problem was also discussed

Dual-Band and Broadband RF Power Amplifiers for Concurrent Signal Transmission

Broadband power amplifiers are becoming increasingly important for communications andradar phased array applications. Amplifying concurrent signals allows for increased data through- put with carrier aggregation and improved radar tracking performance, among other benefits. However, non-concurrent broadband amplifier design is limited in performance by fundamental matching limitations, and suffers further in the concurrent mode due to signal mixing. To reduce the cost of phased arrays, a low-cost GaN-on-Si technology is first investigated on which broadband power amplifiers are designed and fabricated. Various passive structures are simulated to validate process stack-up simplifications, along with the design and characterization of a narrowband proof-of-concept X-band power amplifier. Fundamental limitations are summarized and utilized to develop a design procedure for multi-stage power amplifiers with increased gain for phased array applications. This procedure is confirmed with a fabricated matching network. These results are then used in dual-band and broadband power amplifiers designs, which are fabricated with commercially available GaAs and GaN technologies. Hybrid and MMIC implementations in both cover 2-18 GHz in aggregate. The power amplifier characterization focuses on comparing each implementation in the non- concurrent and concurrent mode to understand the effect each power amplifier has on signal ampli- fication. A new broadband power amplifier architecture is developed to improve the performance of broadband power amplifier amplifying concurrent signals. Results indicate that a PA with this architecture can achieve similar power and efficiency as compared to a standard broadband PA, whereas linearity can be improved and/or simplified using this approach.</p

Voyager spacecraft system. Preliminary design, volume B /book 2 of 3/ - Alternate designs considered - Telecommunications

Voyager spacecraft trade-off design parameters in telecommunication subsystems and between telecommunication system and other systems - data encoder and data storage system