This paper presents a reconfigurable bandpass filter using semi-conductor distributed doped areas (ScDDAs) as active elements. The active and the passive parts are designed in the same way on a ...silicon substrate in microstrip technology. The ScDDAs are able to commute from quarter-wavelength short-circuited stubs to half-wavelength open-ended ones. This co-design method offers a great design flexibility and makes it possible to integrate the active elements in the substrate. In this paper, a two-pole bandpass filter is synthesized at 5 GHz with a 30 % bandwidth in the ON-state (when the stubs are short-circuited) and a 24 % bandwidth in the OFF-state (when the stubs are terminated by an open-circuit). The synthesis is detailed and the simulation and measurement results presented. A good fitting is obtained for these results proving the viability of such an approach.
This paper proposes a reconfigurable (switchable) bandpass-to-bandstop filter configuration with wideband performances. The suggested configuration is easy to design and implement by just using ...transmission line sections, avoiding the use of coupled-line stages. The filter is implemented in silicon technology by using embedded switches which are co-designed along with the transmission lines, which prevents the parasitic effects from SMD components and facilitates the integration with other subsystems and the system-on-chip (SoC) implementation. When the embedded switches are Off, the bandstop filter state is obtained leading to a fifth-order and very selective response along with a very broad upper passband. When they are turned On, a third-order bandpass filter response is achieved with one transmission zero. The proposed configuration also allows a good design flexibility between states. To validate the concept, a prototype centered at 3.0 GHz has been designed and implemented to present a 3-dB fractional bandwidth of 75% for both states, showing a good agreement between simulations and measurements.
In this paper, a quarter wavelength coupled lines X-band bandpass filter (BPF) integrating an attenuator feature is presented. The high rejection analog attenuator uses integrated Semiconductor ...Distributed Doped Areas (ScDDAs) on silicon substrate as tunable resistors. The measured insertion loss of 2.8 dB and attenuation range of 42 dB allow a precise control of the transmitted power for highly integrated systems. A coupled semiconductor physics and electromagnetic structure simulation framework is also proposed in retro-simulations to improve design accuracy of distributed semiconductor devices.
This paper presents a new co-design of a 15 GHz SPDT -antenna for RF seekers. The SPDT -switch permits the commutation between the two possible feeding paths of the antenna and, therefore, a switch ...able polarization between two linear (horizontal and vertical) ones in order to optimize the detection of targets in future RF seekers. Thanks to the silicon substrate, the active elements, i.e., N+PP+ integrated junctions, and the passive parts, i.e., transmission lines and the antenna, are designed and optimized at the same time, which gives some flexibility and degrees of freedom. The flexibility is given by the possibility to choose the doped-areas size and their position avoiding off-the-shelf components that induce parasitic effects at high frequency. The reconfigurability is achieved using integrated semiconductor distributed doped areas (ScDDAs), forming N+PP+ integrated junctions with a chosen length as long as possible to optimize their performances. Firstly, the concept of the SPDT- antenna is discussed followed by the design, the simulations, the fabrication and ending by the measurement of the demonstrator.
A backing with high acoustic attenuation and impedance was fabricated for high-frequency P(VDF-TrFE)-based transducer. Thanks to the low acoustic impedance (4.5 MRayl) of this piezoelectric ...copolymer, it is well adapted acoustically with the propagation medium, whether water or biological tissues. The ultrasonic transducers can have large bandwidths, but the sensitivity can be quite low mainly due to the value of the coupling coefficient lower than standard piezoelectric ceramics (PZT). By choosing a backing with a high acoustic impedance (over 20 MRayl), the sensitivity/bandwidth trade-off of the transducer can be modified to favor sensitivity while keeping a sufficient bandwidth for imaging applications. A metal composite based on sintered bronze, tin and air was fabricated with an innovative process (i.e. impregnation of the tin in the porous sintered bronze). The material delivered an acoustic impedance of 32 MRayl and an attenuation coefficient of 1.2 dB/mm/MHz (in the frequency range 5-35 MHz). It was used for the fabrication of a focused single element transducer. Electro-acoustic response (at the focal distance of 12.7 mm, f# around 2) had a center frequency at 27 MHz, an axial resolution of 50 µm and a fractional bandwidth at -6dB of 65%. B-mode image of a tungsten wire phantom allowed to deduce a lateral resolution of 125 µm. No parasitic echo was observed which confirms the efficiency of this new metal composite.
This paper presents a frequency reconfigurable interdigital filter designed on a semi-conductor substrate. The filter associates parallel-coupled lines and two stubs, where both stubs switch from ...open-ended to short-ended. Therefore, the reconfigurability is achieved by biasing some Semi-conductor Distributed Doped Areas (ScDDAs), which are N + PP + junctions, working as active elements integrated in the substrate. The design method is based on a co-design of the active and the passive parts in a same time. A two order filter validates the co-design approach from the synthesis to the measurements. The filter resonant frequency commutes from 3.5 GHz to 2.2 GHz.
This paper deals with the impact of the doped areas sizes on the performances of microwave switches. The RF switches are designed on a silicon substrate in microstrip technology and use ...semiconductors diodes (N + P junctions) as active elements to commute from the OFF-state to the ON-state. Therefore, the co-design of the microstrip transmission lines and the active elements gives a great design flexibility. The manufacturing process is based on classical steps used to fabricate semiconductor components and this allows to choose the size of the active elements (i.e. the size of the doped areas). Five demonstrators with as many different integrated diode sizes are presented and the size impact on their performances is discussed on the frequency band going from 0.1 GHz to 10 GHz. With a very low bias voltage, the insertion losses are lower than 2 dB and the isolation can be higher than 40 dB.
This paper presents a novel frequency reconfigurable patch antenna where the tunable element is not only integrated in a silicon substrate but also co-designed and manufactured in the same process ...flow as the antenna itself. The active element is based on a N + PP + junction which acts as a switch (OFF- and ON-states). With a low bias voltage (- 1.2 V), one radiated slot is short-circuited to the ground plane on the whole antenna width allowing a tuning frequency of the patch antenna. A demonstrator, which has been characterized and manufactured validates the co-designed method of the resonant frequency antenna. It switches from 11.6 GHz to 17.4 GHz.
This paper deals with the impact of the temperature on tunable resonators with regard to the frequency shift, the current consumption and the insertion losses in the 30 °C to 150 °C range. Two ...different technologies have been selected; the first one is a FR4 technology, where the tunability is performed with a PIN diode, whereas on the second one, the resonators are designed on a silicon substrate with an integrated active element. In each technology, the active component switches from an open-ended to a short-ended resonator. This paper presents three different configurations; one on the FR4 substrate where the resonant frequency switches from 2.8 GHz to 1.45 GHz and two others, on the silicon substrate, where the first resonator is designed in the same frequency range and switches from 2.96 GHz to 2.1 GHz whereas the second one is designed at higher frequency (commutes from 7.3 GHz to 3.9 GHz). Electromagnetic simulations are compared to the measurements and are presented between 30 °C and 150 °C. Current consumption elements are also compared between the two technologies.
