Electromagnetic modeling and optically-controlled micro in GaAs integrated (original) (raw)
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Journal of Catalysis, 2005
A state of the art modeling of microwave photoswitching devices is exposed. A new 3 D electromagnetic modeling allows the design of an optically-controlled microwave phase shifter microwave starting from the traditional circuit of a microwave photoswitch. Measurements of the parameters S of this optically-controlled microwave phase shifter attests the function of this circuit by optical way and highlights the interest of the integration of this new type of microwave phase shifters in systems of antennas arrays. A new optically-controlled microwave phase shifter with a patented structure is under development.
Photo-devices for optical controlling of microwave circuits
Journal of telecommunications and information technology, 2001
The most important optical devices which can be used for controlling microwave circuits will be presented in the paper. The performance and the parameters of the devices such as semiconductor microwave optoelectronic switches, photodiodes and phototransistors were described. The influence of the optical illumination on their microwave parameters will be described in details, including the our own investigations and simulations results. Several applications of such devices and their potential possibilities will be presented.
Optically Controlled Microwave Digital Phase Shifter
We propose a novel kind of 1-bit optically controlled digital phase shifter. It is loaded transmission line the phase shifter having true time delay (TTD) performance. It is based on the optical switching of the DGS (defected ground structure) slot for the microstrip line on the semi-insulating Sisubstrate. Phase shifter is designed at 4.8 GHz. The 1-bit phase shifter has insertion loss, 0.05 dB, return loss -28.29 dB and phase deviation 1 0 . The cascading of I bit phase shifters can provide higher bit phase shifter. The performance of the phase shifters has been simulated in the MOM based 2D-EM Simulator, Ensemble.
Analysis of Optically Controlled Microwave/Millimeter-Wave Device Structures
IEEE Transactions on Microwave Theory and Techniques, 1986
The light-Induced voltage and the change 1n the source-to-drain channel current under optical Illumination higher than the semiconductor bandgap for GaAs MESFET, InP MESFEI, A1 0 3 Ga 0 7 As/GaAs high electron mobility transistor (HEM!) and GaAs permeable base transistor (PBT) were analytically obtained. The GaAs PB1 and GaAs MESFEI have much higher sensitivity than InP MESFEI. The A1 0 3 Gag-/As/GaAs HEMT 1s observed to have the highest sensitivity. Var1 atlon in device .parasitlcs due to optical Illumination and its effect on the cutoff frequencies f-| and f max are also Investigated. INTRODUCIION Direct optical control of microwave devices in GaAs monolithic microwave integrated circuits (MMlC's) can result in better switching, amplitude and phase control in amplifiers, and frequency control in oscillators (ref. 1). Furthermore, 1t allows use of optical fiber technology for the Interconnecting MMIC's, thereby reducing cross talk and electromagnetic Interference. It also enhances efficiency and speed of operation (ref. 2). *NRC-NASA Research Associate.
Intermixing optical and microwave signals in GaAs microstrip circuits and its applications
Microwave and Optical Technology Letters, 1993
response is small, associated with the gate junction and resembles a photodiode. These facts explain the small locking range achieved by optical injection locking. For switching applications the large photovoltaic effects can b e utilized; however, the rise and fall times are typically in the microsecond range, which means that the device is limited to switching rates of several megahertz. 6. CONCLUSIONS In this article we have reviewed the phenomenon of light interaction with MESFET. T h e importance and applications of this photodetection have been explained, and the physical mechanisms were described. It was shown that the response to modulated light is quite different from the response to constant illumination. In general, the MESFET is a relatively "slow" photodetector, and its response decreases strongly with frequency. A t low frequencies and dc the response is very large, and exhibits gain, but at microwave frequencies the response is small and similar t o a photodiode. Despite the above, the MESFET is useful a t high frequencies for applications such as injection locking and optical mixing, which cannot be obtained by photodiodes.
Demonstration of a photonically controlled RF phase shifter
IEEE Microwave and Wireless Components Letters, 1999
Integrated photonic radio frequency (RF) phase shifters with dc voltage control have been realized using a nested dual Mach-Zehnder modulator configuration in a new nonlinear optical polymer, CLD2-ISX. These modulators have a Vπ of 10.8 V and exhibit excellent frequency performance measured up to 20 GHz. A near linear phase shift exceeding 108° was obtained for a 16-GHz microwave signal by tuning the dc control voltage over a 7.8-V range. It is expected that these integrated polymer phase shifters will find widespread applications in new types of lightweight optically controlled phased array systems
On the improvement of the performance of the optically controlled microwave switch
IEEE Transactions on Microwave Theory and Techniques, 1997
In this paper, a new design for the gap used as an optically controlled microwave switch is proposed. This new design is based on the use of a rib structure in the gap region. The proposed structure is studied using the finite-difference method (FDM). Obtained results show that for small gaplengths, the structure figure of merit, defined as the product of the ON/OFF ratio and the bandwidth, can be improved by about 38 dB 3 GHz.
GaAs metal–semiconductor–metal Schottky microwave optical switches
Optics & Laser Technology, 2013
The aim of our work was to integrate Schottky MSM photodetectors in the central strip of coplanar lines for microwave switching application. The MSM photodetectors in the microwave lines have an active surface of 3 Â 3 mm 2 and electrode spacing of 0.2, 0.3, 0.5 and 1 mm. The characterization of the structures in darkness and under illumination allowed us to obtain On/Off ratio of 26-28 dB at 20 GHz and 25 GHz. These results demonstrate that the structures show a good performance for microwave photoswitching which means good insulation in darkness and low insertion losses under illumination.
2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017)
Monolithic optically variable capacitors (OVC's) consisting of photovoltaic arrays integrated with varactor diodes are used in bias free optical control of microwave circuits and antennas. The improved OVC's presented here required only 450 pW of optical power for a 2.2:l change in capacitance, a threefold reduction in optical power compared to previous results. Using these improved OVC's, bias free optical control of phase shifters and slot antennas has been demonstrated with the lowest reported optical power.
Characterising the linearity of an optically controlled photoconductive microwave switch
2010 Loughborough Antennas & Propagation Conference, 2010
The linearity response of a photoconductive switch under incident 2GHz microwave signal power of 1W is presented. A silicon switch is illuminated with a range of optical intensities at a wavelength of 980nm in order to characterise the linearity in terms of harmonic content. Reported single tone third order intercept (TOI) was measured as 63dBm under 200mW optical incident light. The study presents photoconductive switches as a promising alternative to conventional microwave switches in high power applications.