A comprehensive study of high-selectivity filters that employ series multiconductor transmission lines (MTLs) and a shunt MTL is presented. It is shown that this topology is suitable for implementing three- and five-pole bandpass filters having a quasi-elliptic frequency response. An exact synthesis procedure with analytical design equations for achieving equal-ripple passband response as a function of the operating bandwidth is described. To validate the theory, several bandpass filters are designed, fabricated, and measured. The excellent agreement between the measurements and the predicted results validates the proposed procedure as a reliable and quick technique for designing wideband quasi-elliptic bandpass filters.

In this paper, an FPGA-based channel emulator for indoor power line communications (PLC) is described. It has been designed for a band up to 30 MHz and is able to emulate time-varying channels and to generate a great variety of disturbances.

The design of dual-band bandpass filters consisting of series short-circuited wire-bonded multiconductor transmission lines and shunt open stubs is thoroughly carried out in this paper. Two different configurations are studied, and closed-form analytical design equations are derived to synthesize Chebyshev filtering functions. A novel, simplified, and time-saving synthesis procedure to design dual-band filters with narrow or moderate broad bandwidths is finally presented, attending to the required final specifications and the physical and manufacturing limitations. The usefulness and validity of the proposed analytical equations are illustrated by designing, manufacturing, and measuring three different prototypes, showing an excellent agreement between analytical and measured results.

In this short communication we want to discuss the reply given in [1] to our comments in [2]. In [2], we analyzed and corrected the equation proposed in [3] to compute the equivalent characteristic impedance of a short-circuited coupled-line section [Fig. 1(a)], but in [1], the same authors maintain that theory in [3] is correct. Therefore, in this work the analytical equation obtained in [2] is assessed and compared to the equation given in [1], [3] with the help of an electromagnetic solver based on the method of moments.

A compact topology for implementing compact multiband bandpass filters is presented in this paper. To achieve the desired frequency response, two identical short-circuited multiconductor transmission lines (MTLs) and properly connected shunt open stubs are interconnected. Using this configuration, it is possible to design multiband bandpass filters effortlessly. As both the MTLs and the stubs are distributed elements, spur-line band-stop filters are added to mitigate the first replica of the structure’s frequency response. To assess the behavior of the developed filter design procedure, a prototype consisting of a six fingers-MTL and two shunt open stubs has been designed, manufactured, and analyzed, showing excellent agreement between analytical and measured results, considering that no simulation or optimization process has been performed during the design process, just for result verification. Furthermore, it is possible to establish a design criterion that allows the fast and reliable synthesis of multiband responses by varying just a small number of geometrical parameters of the MTLs and the corresponding stubs.

This work presents a monolithic transmit/receive (T/R) frontend covering the 6–18-GHz frequency band and implemented in 150-nm gallium-nitride (GaN) technology. The benefits of single-die integration are harnessed through a top-down, system-level co-design approach, where specifications and system tradeoffs are addressed directly at the die level: an asymmetric T/R switch simplifies the transmit path to save for output power and efficiency, while its receive branch is merged with the low-noise amplifier’s input matching network for improved compactness and sensitivity; the floorplan is optimized from the start, implementing single-side biasing for all subcircuits to minimize T/R coupling. On-wafer measurements demonstrate an average transmit output power of 9.5 W (minimum of 5.6 W) with 19.4% efficiency (minimum of 13.5%) across the target bandwidth. In receive mode, the prototypes achieve over 21-dB gain with an average noise figure of 3 dB (maximum of 3.3 dB). These results are consistent with, and in some aspects exceed, those reported in the literature for ultrawideband GaN-based single-chip T/R frontends. Furthermore, the prototypes were also successfully tested in bare–die configuration on a custom evaluation fixture, confirming robust performance under realistic system conditions with only minor degradation compared with on-wafer measurements.