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This paper presents a magnetically coupled bandpass filter (BPF) approach for power distribution to multiple implanted devices. The BPF design approach accounts for the multiple loads and enables maximum power transfer into each individual receiver for given coupling coefficients between the coils. The proposed concept is demonstrated by showing power distribution to two identical receivers below...
A structure for positive-to-negative interresonator coupling in cavity resonator filters is shown in this paper. Mechanically and electrically reconfigurable versions of the structure are described. The structure has a wide spurious free range while retaining the capability to provide near-zero coupling because it uses symmetry to redirect digitally addressable amounts of current to adjust coupling...
In order to enable multifunction arrays with simultaneous transmit and receive, high isolation must be provided between antenna elements. This isolation should ideally be independent of the waveforms being transmitted. In this paper, a tunable baffle design is presented which provides over 30 dB of improvement in isolation for bandwidths of 7.5 MHz between adjacent antennas. This isolation can be...
This work demonstrates the utilization of digital at every element signal generation to show the effect of directional modulation for radar. For example, where the code modulation used for pulse compression can be changed as a function of angle, such that the code of interest is only generated at the direction of the beam with different codes appearing just off the beam axis, allowing for angular...
In this paper we demonstrate a method of practically designing a large electrical volume coaxial structure for room-temperature chirped pulse Fourier transform microwave (RT-CP-FTMW) chemical sensing. Both the center and outer conductor are tapered to optimize the volume of molecular analysis while minimizing coupling to higher-order modes in the electrically large coax because they limit the turn...
Coupling matrices are often used to design modern microwave filters. They are useful, as they can directly relate the coupling strengths of a set of coupled resonators to the filter response. However, given a physical filter geometry it can be difficult to find the exact terms of the coupling matrix from traditional measurements.
A room-temperature chirped pulse Fourier transform microwave spectrometer was recently demonstrated using a WRD750 double ridge waveguide. The operation frequency range, 7.5 GHz to 18 GHz, is limited by the waveguide, and the effective sensing area is confined within the small region between the two ridges. This paper shows a new overmoded coaxial cable spectrometer design utilizing a Hamming function...
A two-pole, substrate-integrated, high quality(Q)-factor absorptive bandstop filter is demonstrated that exhibits enhanced selectivity over traditional reflective bandstop filter designs and higher Q-factor components than previous absorptive designs. With a Q-factor of 729, the presented filter has a peak isolation of 30 dB, a narrow 10-dB rejection bandwidth of 3.9 MHz that is tunable over 3.4–3...
This paper shows measurement of intraocular pressure (IOP) within a mouse eye. Three main challenges faced the development of a device for the measurement: the size of the mouse eye, the depth of the anterior chamber where the device will be implanted, and the maximum allowable incision size. These factors all limit the size of the device. In addition, a novel detection scheme is required which enables...
A small three element linear planar array designed to have high isolation between elements for Simultaneous Transmit And Receive (STAR) is demonstrated. This high isolation is achieved through use of tunable resonators that control the near fields of the array without detrimentally affecting the radiated fields. These resonators, which are placed between the patch antenna elements of the array, provide...
Wireless powering holds immense promise to enable a variety of implantable biomedical measurement systems with different power supply and current budget requirements. Effective power management demands more functionality in the headstage design like power level detection for range estimation and power save modes for sleep-wake operation. This paper proposes a single chip ASIC solution that addresses...
RF ion traps are a principle means for molecule separation used in mass spectrometry based chemical sensors. Until recently the lab confined mass spectrometer has been too expensive and cumbersome for field based analysis. Advancements in packaging and electronics have led to smaller instrumentation and even more so, the miniaturization of the electric field based ion trap leads to lower voltage and...
We present, for the first time, an all-silicon magnetostatically-tunable evanescent-mode cavity resonator that is capable of analog tuning from 9.5 to 17 GHz (1∶1.8) while maintaining a high unloaded quality factor (Q) of 650–950 (70–80% of the simulated results). The resonator is fabricated using silicon micromachining and is tuned by moving a gold-covered single-crystal silicon diaphragm over the...
A unique GaN power amplifier (PA) with an integrated evanescent-mode resonator as its output matching network is presented in this paper. Instead of matching the output of the GaN transistor to 50 Ω and connecting it to a 50-Ω bandpass filter, the GaN is directly integrated with a one-pole filter thus eliminating the conventionally-employed output matching network after the GaN transistor. This leads...
This paper presents the fabrication of an ultra-thin tag for identification and sensing applications in extremely small implantable regions. Particularly, we are demonstrating the capability to create a telemetry system which is implantable in a mouse eye. This system will eventually be able to monitor intraocular pressure (IOP). The small size of the mouse eye presents challenges for surgery and...
Tunable bandstop filters are demonstrated with wide tuning ranges, tunable bandwidth, and a variable number of dynamically allocated poles. The number of poles can be dynamically applied at different frequencies to maximize isolation for a given interference scenario. These filters are made with evanescent-mode cavities which use a new loading post geometry that results in greater external coupling...
A novel all-Parylene based multilayer organic interposer for high-density 3D packaging is presented. The multilayer interposer consists of both a thick 50µm Parylene substrate layer as well as thin layers, down to ∼50 nm, which are formed by successive conformal thin-film deposition. The processing of the layers utilizes standard thin film techniques such as photolithography, dielectric/metal deposition,...
This paper demonstrates the concept of a field-programmable filter array which can be configured in the field after fabrication. The proposed array is composed of tunable resonators and can have multiple functionalities by rerouting signals from input ports to output ports. Signal rerouting can be achieved by controlling the inter-resonator coupling with a wide tuning ratio of coupling coefficients...
Concurrent transmit and receive with multiple antennas is demonstrated through near field cancellation. Full-duplex operation is possible through cancellation of the transmit signal at the receiver as much as 50dB. By exploiting symmetry in an array of antennas, a centrally located receiver is able to operate without saturation in the presence of high power transmit signals. The transmitters are able...
This paper presents for the first time a novel concept for monitoring the resonant frequency of electrostatic MEMS tunable high-Q evanescent-mode cavity resonators through capacitance measurement. The proposed scheme relies on the fact that there is a one-to-one correspondence between the actuation capacitance Cs and the resonant frequency f0. This relationship is derived theoretically using a spring-mass...
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