Planar limiters and receiver protectors

Coaker, B.M.; Dowthwaite, D. Mark

doi:10.1109/eumc.2007.4405537

Cited by 3 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We investigate the corresponding RF S-parameter properties up to 13.5 GHz and power handling capabilities for possible RF applications in high frequency filters, modulators, and active microwave device components. 3,5,[10][11][12][13][14][15][16] We show that high RF input power can reduce the resistance of VO 2 similarly as applied DC voltage. We compare transient and RF properties with published results on VO 2 and present lumped circuit element and 3D electromagnetic simulations that model the RF properties quite well.…”

Section: Introductionmentioning

confidence: 99%

Electrical switching dynamics and broadband microwave characteristics of VO2 radio frequency devices

Zhou

Fisher

et al. 2013

Journal of Applied Physics

100

View full text Add to dashboard Cite

Vanadium dioxide is a correlated electron system that features a metal-insulator phase transition (MIT) above room temperature and is of interest in high speed switching devices. Here, we integrate VO 2 into two-terminal coplanar waveguides and demonstrate a large resistance modulation of the same magnitude (>10 3 ) in both electrically (i.e. by bias voltage, referred to as E-MIT) and thermally (T-MIT) driven transitions. We examine transient switching characteristics of the E-MIT and observe two distinguishable time scales for switching. We find an abrupt jump in conductivity with a rise time of the order of 10 ns followed by an oscillatory damping to steady state on the order of several μs. We characterize the RF power response in the On state and find that high RF input power drives VO 2 further into the metallic phase, indicating that electromagnetic radiation-switching of the phase transition may be possible. We measure Sparameter RF properties up to 13.5 GHz. Insertion loss is markedly flat at 2.95 dB across the frequency range in the On state and sufficient isolation of over 25 dB is observed in the Off state.We are able to simulate the RF response accurately using both lumped element and 3D electromagnetic models. Extrapolation of our results suggests that optimizing device geometry can reduce insertion loss further and maintain broadband flatness up to 40 GHz.2

show abstract

Section: Introductionmentioning

confidence: 99%

Electrical switching dynamics and broadband microwave characteristics of VO2 radio frequency devices

Zhou

Fisher

et al. 2013

Journal of Applied Physics

100

View full text Add to dashboard Cite

show abstract

“…Removing part of the PIN junction area using mesa construction can reduce the parasitic capacitance but detrimentally increases the diode's transient thermal impedance [ 6 ]. Alternatively, the Schottky diode can be isolated from the RF path with either a high-impedance quarter wave line [ 7 ] or directional coupler [8] - [9], but these passives add to either the size or the cost, and also increases the limiting threshold. The capacitive loading of the signal path can be reduced by connecting the diodes to a lower impedance (12.5 ohm) node [ 10 ], but the required impedance transformers are lossy and space-consuming.…”

Section: Introductionmentioning

confidence: 99%

Limiting and transient performances of a low loss PIN-Schottky limiter

Lim¹

2013

2013 IEEE International RF and Microwave Conference (RFM)

View full text Add to dashboard Cite

The main cause of loss in the PIN-Schottky limiter is the diodes' parasitic capacitances. Techniques to counter the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice cost, manufacturability, size, performances or thermal ruggedness. To reduce loss in the PIN-Schottky limiter, we re-configured its parasitics into a low pass ladder network. This paper reports on the new configuration's changed large signal and transient performances. We observed improved isolation at 0.9 and 2.4 GHz, and a beneficial reduction in the initial energy that slips through the limiter before limiting begins. In conclusion, this configuration simultaneously improves insertion loss, matching, isolation and spike leakage suppression. It has the potential to improve limiting performances in wideband receivers for wireless communication and medical imaging.

show abstract

“…This sheet beam topology is particularly of interest in the millimeter wave band devices at frequencies >100 GHz where the familiar P $ f 2 scaling no longer holds with a dramatic decrease in power observed in the "THz gap" that lies between the electronics and photonics areas of research. 9,10 In addition to the ability to transport higher power for reasonably efficient beam-wave interaction, the planar structures are relatively easier to fabricate using unconventional/MEMS fabrication schemes like LIGA, 11,12 EDM machining, 13,14 Si DRIE, 4 and nano-CNC milling. 11,12,15 This paper presents the RF transmission measurements (cold test) results of the Sheet Beam TWTA in the 170 GHz-270 GHz frequency range that is fabricated by state-of-the-art nano CNC-milling process 16 and diffusion bonded in a three layer topology.…”

Section: Introductionmentioning

confidence: 99%

0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis

et al. 2012

View full text Add to dashboard Cite

Measurements of parallel electron velocity distributions using whistler wave absorption Rev. Sci. Instrum. 83, 083503 (2012) HELIOS: A helium line-ratio spectral-monitoring diagnostic used to generate high resolution profiles near the ion cyclotron resonant heating antenna on TEXTOR Rev. Sci. Instrum. 83, 10D722 (2012) Microwave Doppler reflectometer system in LHD Rev. Sci. Instrum. 83, 10E322 (2012) Design of a millimeter-wave polarimeter for NSTX-Upgrade and initial test on DIII-D Rev. Sci. Instrum. 83, 10E321 (2012) Design of the reflective optics for Tore Supra ECEI system Rev. Sci. Instrum. 83, 10E318 (2012) Additional information on Phys. PlasmasIn this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2-3 lm and surface roughness was measured within 30-50 nm. The RF measurements were conducted with an Agilent PNA-X network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S 21 ) for both the short section and long section (separated by a sever) was measured as $À5 dB while the return loss was generally around $À15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of $45 GHz with an operating frequency at 220 GHz. However, the measured S 21 was $3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz-270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 lm, which is inevitably induced by nano-machining. Furthermore, the S 21 value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted to be reduced from 90 W (for ideal conductivity/design Sparameters) to 70 W (for the measured S-parameters/inferred conductivity) for an average input power of 50 mW. The gain of the tube remains reasonable: $31.4 dB with an electronic efficiency of $1.4%. The same analysis was also conducted for several frequencies between 190 GHz-260 GHz. This detailed realistic PIC analysis demonstrated that this nano-machined TWT circuit has slightly reduced...

show abstract

Planar limiters and receiver protectors

Cited by 3 publications

References 1 publication

Electrical switching dynamics and broadband microwave characteristics of VO2 radio frequency devices

Electrical switching dynamics and broadband microwave characteristics of VO2 radio frequency devices

Limiting and transient performances of a low loss PIN-Schottky limiter

0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis

Contact Info

Product

Resources

About