Papers by Johannes Benedikt
Cancer Research, 2021
Background: Current and existing ablation for cancer treatment such as laser, RF and MW, all indu... more Background: Current and existing ablation for cancer treatment such as laser, RF and MW, all induce local high temperatures. The hyperthermia generated by these techniques lead to burns, pain and unwanted side effects in patients. Consequently, we aimed to develop a normothermic pulsed electric field exposure (PEFE) treatment that when applied in cancer treatments can effectively induce cell death and tumour degeneration without associated physical consequences. Method: The pulsed electric field exposure (PEFE) was generated with a carrier signal at 5.8GHz, then transmitted by a pointed open-ended coaxial cable. Breast cancer cells were treated with PEFE and assessed for their viability, apoptosis and other biological responses, together with the intracellular signalling events by using protein kinase array and related technologies. Breast cancer cells were also assessed for their ultrastructure changes by electron microscopy. In vivo experimentation was used to determine efficacy u...
Posters, 2021
higher proportion of diarrhoeal samples tested positive to Campylobacter (12%) compared to the no... more higher proportion of diarrhoeal samples tested positive to Campylobacter (12%) compared to the non-diarrhoeal control group (5%). Unlike the diarrhoeal samples, no control samples yielded positivity to Vibrio cholerae, Cyclospora cayetanensis, Astrovirus, Rotavirus A or Sapovirus Conclusions Detection of high levels of polymicrobial enteric infections are prevalent in Central Indian symptomatic and asymptomatic populations. E. coli pathotypes predominate in both urban and rural settings. Further studies are required to understand the clinical significance of these mixed infections, as well as how best to manage them.
Posters, 2021
higher proportion of diarrhoeal samples tested positive to Campylobacter (12%) compared to the no... more higher proportion of diarrhoeal samples tested positive to Campylobacter (12%) compared to the non-diarrhoeal control group (5%). Unlike the diarrhoeal samples, no control samples yielded positivity to Vibrio cholerae, Cyclospora cayetanensis, Astrovirus, Rotavirus A or Sapovirus Conclusions Detection of high levels of polymicrobial enteric infections are prevalent in Central Indian symptomatic and asymptomatic populations. E. coli pathotypes predominate in both urban and rural settings. Further studies are required to understand the clinical significance of these mixed infections, as well as how best to manage them.
Optics Express
Photonic microwave generation based on period-one dynamics of an optically injected VCSEL has bee... more Photonic microwave generation based on period-one dynamics of an optically injected VCSEL has been study experimentally. The results have shown that the frequency of the generated microwave signal can be broadly tunable through the adjustment of the injection power and the frequency detuning. Strong optical injection power and higher frequency detuning are favorable for obtaining a high frequency microwave signal. These results are similar to those found in systems based on distributed feedback lasers and quantum dot lasers. The variation of the microwave power at the fundamental frequency and the second-harmonic distortion have also been characterized.
IEEE Antennas and Wireless Propagation Letters
This letter presents the design of a Ka-band active integrated antenna in package (AIAiP). A mono... more This letter presents the design of a Ka-band active integrated antenna in package (AIAiP). A monolithic microwave integrated circuit amplifier based on the GaAs process and a compact patch antenna based on the printed circuit board process are implemented, respectively. Then, the amplifier and antenna are assembled together in a specified package using the wire-bond process. Thus, compared to the traditional solutions, the transmission loss and the size of the proposed AIAiP are significantly reduced. Furthermore, the influence of the bonding wire and the package is taken into account in the design of the amplifier and the antenna, respectively. A good agreement between the simulation and measurement results can be observed. The proposed AIAiP occupies a compact size of 7 × 7 mm 2. Meanwhile, it achieves −10-dB impedance bandwidth from 33.4 to 37.2 GHz and a peak gain of 18.9 dBi at 35 GHz. Additionally, the impact of the package size on the antenna performance has been demonstrated for future AIA designers. Index Terms-Active integrated antenna (AIA), antenna in package, GaAs amplifier. I. INTRODUCTION A CTIVE integrated antenna (AIA) refers to the antenna integrated with one or more active solid-state devices. The AIA has received considerable interest due to its advantages in low loss and compact size, and is much more suitable for the phased-array antenna systems [1], [2]. Several kinds of AIAs
2016 16th Mediterranean Microwave Symposium (MMS), 2016
Solid state power amplifiers are ordinarily fitted with an isolator at the output port to protect... more Solid state power amplifiers are ordinarily fitted with an isolator at the output port to protect the transistors from large variations in the load impedance. Using GaN transistor technology should allow safe transistor operation to higher field levels and also to higher channel temperatures, which may remove the necessity for the isolator component - reducing circuit losses, and reducing circuit
Solid state amplifiers are often fitted with an isolator component on the output to protect them ... more Solid state amplifiers are often fitted with an isolator component on the output to protect them from impedance mismatch. GaN based HFET's could offer the potential to remove the isolator due to their high breakdown voltages and high channel temperature operation. However the absence of an isolator would mean that the transistor would have to be able to withstand any
High Frequency Postgraduate Student Colloquium, 2005, 2000
ABSTRACT
2008 IEEE MTT-S International Microwave Symposium Digest, 2008
This paper demonstrates that by robust waveform engineering it is possible for high power Si LDMO... more This paper demonstrates that by robust waveform engineering it is possible for high power Si LDMOS to achieve very high efficiency at frequencies up to 2.1 GHz. Class F amplifier operation was realized in a 5W LDMOS device by the successful application of robust waveform engineering procedures; undertaken at the current generator plane. The peak power added efficiency was found to be 78% at 0.9GHz and 77% at 2.1GHz. In both cases the RF waveforms were optimized in terms of the gate voltage, fundamental and harmonic impedances. The main difference at 2.1GHz was the change in fundamental impedance to a more reactive impedance to compensate for the dynamic device output capacitance. To the authors' knowledge this is the highest efficiencies reported in the literature for Si LDMOS devices at 2.1GHz.
2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157), 2001
ABSTRACT Analytical nonlinear model validation through large-signal time-domain characterization ... more ABSTRACT Analytical nonlinear model validation through large-signal time-domain characterization has been greatly improved, by establishing a novel link between measurement and simulation. Investigation on a silicon LDMOS device and its nonlinear electro-thermal model positively identifies links between model formulation and amplifier requirements for future telecommunication systems
IEEE MTT-S International Microwave Symposium Digest, 2003, 2003
Abstract The Doherty PA configuration has become well established as a means of enhancing PA effi... more Abstract The Doherty PA configuration has become well established as a means of enhancing PA efficiency. The improvement, however, is usually accompanied by deterioration in overall linearity. This paper addresses two important features of the ...
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Papers by Johannes Benedikt