Ceyhun Karpuz | Pamukkale University (original) (raw)

Papers by Ceyhun Karpuz

Computer Applications in Engineering Education

In this paper, two new subdesign tools including the quasi‐static and fuzzy model calculations fo... more In this paper, two new subdesign tools including the quasi‐static and fuzzy model calculations for the electrical parameters of the coupled planar transmission lines used in the design of microwave communication subsystems including resonators, filters, and multiplexers are presented for CADMFILT software. Proposed subdesign tools have properties such as electrical parameter calculations for microwave circuit analysis/synthesis, fuzzy logic model applications, comparisons, and graphical demonstrations. The first subdesign tool can calculate the electrical parameters of the coupled planar transmission lines by using the quasi‐static analysis method. The other tool is based on subtractive fuzzy clustering, which can offer approximate solutions as an alternative to numerical and analytical closed‐form expressions of quasi‐static analysis. The proposed subdesign tools have a competent and efficient algorithm to provide fast, accurate, and sensitive results. To test the accuracy of these...

In this paper, a novel microstrip bandstop filter with tunable center frequency and bandwidth is ... more In this paper, a novel microstrip bandstop filter with tunable center frequency and bandwidth is introduced. A dual-mode square loop resonator and three varactor diodes are used to achieve the tunability operation. The dual-mode square loop resonator is coupled to a straight transmission line that connects input and output ports. One of the varactors is used as a perturbation element on the symmetrical axis of the resonator and even mode resonance frequency can be tuned by changing the capacitance of its. Remaining two varactors are located at the lateral arms of the resonator as reference elements and they have task on the tunability of the odd mode resonance frequency. Depending on the capacitance changes of the varactors, both of center frequency and bandwidth of the stopband can be tuned. The designed filter was also fabricated and measured for the experimental verification of the predicted results.

In this paper, three microstrip wideband bandpass filters having three, five and seven poles are ... more In this paper, three microstrip wideband bandpass filters having three, five and seven poles are designed by using parallel-coupled asymmetric three line structures. The proposed filter structures have parallel-coupled asymmetric line blocks having unequal strip widths and coupled each other with coupling gaps. Multi pole frequency responses are resulted from the cascaded parallel coupled transmission lines. The designed filters have adjustment elements as capacitive patches on asymmetrical three line blocks to enhance the control of in-band return loss levels. Approximate theoretical analyses of each filter are realized by introducing ABCD matrices. Three microstrip wideband filters are designed, analyzed and fabricated. Measurement results show good agreements with predicted results.

AEU - International Journal of Electronics and Communications

Drones

The use of robotic systems in logistics has increased the importance of precise positioning, espe... more The use of robotic systems in logistics has increased the importance of precise positioning, especially in warehouses. The paper presents a system that uses virtual fiducial markers to accurately predict the position of a drone in a warehouse and count items on the rack. A warehouse scenario is created in the simulation environment to determine the success rate of positioning. A total of 27 racks are lined up in the warehouse and in the center of the space, and a 6 × 6 ArUco type fiducial marker is used on each rack. The position of the vehicle is predicted by supervised learning. The inputs are the virtual fiducial marker features from the drone. The output data are the cartesian position and yaw angle. All input and output data required for supervised learning in the simulation environment were collected along different random routes. An image processing algorithm was prepared by making use of fiducial markers to perform rack counting after the positioning process. Among the regre...

2023 IEEE Radio and Wireless Symposium (RWS)

Journal of Electromagnetic Waves and Applications

Abstract In this paper, an electronically switchable quad-band microstrip bandpass filter is desi... more Abstract In this paper, an electronically switchable quad-band microstrip bandpass filter is designed using varactor perturbed dual-mode resonators. For this purpose, four meandered dual-mode square loop resonators (DMSLRs) having reference patches are nested and varactor diodes are used to serve as perturbation elements. The designed resonator is analyzed by deriving even/odd mode resonance conditions. S-parameters are also calculated according to the even and odd mode input impedances. Stub loaded feedlines are used to couple the DMSLRs to Input/Output (I/O) ports. According to the capacitances of varactor diodes, each passband can be independently turned on and off. Coupling scheme and coupling matrix of the designed filter are introduced to realize the coupling descriptions. Switching operations are also investigated over the frequency responses obtained from coupling matrix. Passbands of the filter are adjusted to 1.4, 1.7, 2.25, and 2.7 GHz. The designed filter was also fabricated and measured results show a good agreement with the simulated and theoretical results.

Novel diplexer and dual-band filter using a squire open-loop with inset feeding and folded lines ... more Novel diplexer and dual-band filter using a squire open-loop with inset feeding and folded lines are proposed for wireless communication systems. These structures have a compact size. Simulations and experimental results have verified that these structures provide a good performance to be have single pair of transmission zeros at finite reel or imaginary frequencies. The bandpass filters utilizing open-loop having an inset feeding has more coupling characteristics than that of a filter realized employing conventional microstrip open-loop resonator. The modes in the pass-band and the location of transmission zeros can be easily controlled by inset deep, the length of the folded arms that they are coupled to each other by adjusting their length, and by relocating of resonators with two different forms. Consequently, two diplexers and two dual-band bandpass filters with adjustable transmission zeros are designed and realized to use in wireless communication systems

2022 IEEE International Conference on RFID (RFID)

Microwave and Optical Technology Letters

Bulletin of Engineering Geology and the Environment, 2022

Hard rocks can be excavated difficultly by some mechanical miners such as roadheaders. Tunnel bor... more Hard rocks can be excavated difficultly by some mechanical miners such as roadheaders. Tunnel boring machines (TBMs) can excavate hard rocks, but the cost is high due to low advance rate and high tool wear. The difficulties in hard rock excavation can be overcome by exposing hard rocks to microwave energy while cutting. This study investigates influence of mineralogy on the microwave assisted cutting of igneous rocks. The normal and cutting forces were measured during the cutting tests, and the specific energy values were calculated. The optimum specific energy (SE opt .) values reduce quite steadily with the increasing microwave power. The SE opt . of some tested crystalline rocks first increases at the low power (3 kW) and then decreases at the high power (6 kW). The losses in the SE opt . range from 22.5 to 38.7% at the power of 6 kW. The equations were also developed for the estimation of the SE opt . loss. Concluding remark is that the same rock types may be affected differently by microwave energy because of the different mineral types and percentages, and thus they behave diversely under cutting tests. The derived equations will be useful for the prediction of the SE opt . loss due to the microwave treatment.

2020 IEEE Asia-Pacific Microwave Conference (APMC), 2020

Microstrip dual band bandpass filters using the capacitively loaded patch and short-circuited stu... more Microstrip dual band bandpass filters using the capacitively loaded patch and short-circuited stub is presented. The proposed topology is occurred by adding short-circuited stub in the center of a main transmission line and square patches on both sides of the stub in two different forms. The bandwidth and modes of the both passbands are controlled by adjusting the parameters associated with the stub and patch, appropriately. Two different paths are used between the input and output ports to obtain two different filtering characteristics. The proposed circuits are fabricated and measured to demonstrate the experimental verification. The measured and simulated results exhibit good agreement.

2020 50th European Microwave Conference (EuMC), 2021

A novel microstrip diplexer with closely spaced channels is introduced by using stub loaded dual-... more A novel microstrip diplexer with closely spaced channels is introduced by using stub loaded dual-mode square loop resonators (DMSLRs). The proposed resonator is constructed by locating open-circuited stubs with narrow slits to the midpoints of a conventional DMSLR to achieve size reduction. By changing the number of narrow slits, resonant frequencies of the proposed resonator can be controlled. In order to design a diplexer with low channel frequency ratio, two stub loaded DMSLRs having different number of narrow slits are coupled to input and output ports by thin film capacitors. The designed diplexer was also fabricated and measured with a channel frequency ratio of 1.10. The channels were measured at 1.78 GHz and 1.96 GHz with the fractional bandwidths (FBW) of 5.4% and 5.3%, respectively. The measured insertion losses of the channels are 1.99 dB and 1.78 dB. Isolation between the output ports was obtained as better than 28 dB.

Microwave and Optical Technology Letters, 2017

ones. The measured results show the NGD value of the twostage RNGDC can vary from 20.5 ns to 22.5... more ones. The measured results show the NGD value of the twostage RNGDC can vary from 20.5 ns to 22.5 ns with a signal attenuation varying from 21.5 dB to 23.6 dB at a fixed center frequency of 1.73 GHz as the bias voltage (Vc) tuning from 5.82 V to 4.82 V. The two-stage RNGDC in this work is compared with the previously-reported RNGDCs. Main performance parameters are presented in Table 2. It is seen that the proposed two-stage circuit in this work has advantages in signal attenuation and circuit size.

2008 Asia-Pacific Microwave Conference, 2008

The use of dual-mode microstrip resonators such as circular ring, triangular patch, circular disk... more The use of dual-mode microstrip resonators such as circular ring, triangular patch, circular disk or square loop resonators to realize microstrip bandpass filters has been known since Wolff was proposed a dual-mode bandpass filter using a dual-mode ring resonator [1]. Many ...

2016 Asia-Pacific Microwave Conference (APMC), 2016

World Congress on Electrical Engineering and Computer Systems and Science, 2020

The structure proposed in this study is basically a meander-shaped resonator structure. By changi... more The structure proposed in this study is basically a meander-shaped resonator structure. By changing certain parameters determined on this structure, the filtering characteristics can be adjusted. For instance, the bandpass filtering characteristic can be adjusted as elliptical or linear phase by means of adjustments made in the value of the capacitor added to the structure. The effects of coupling and perturbation level on the frequency response in the proposed structure are also investigated. If the coupling level is not sufficient, the filter does not respond. In the proposed filter structure, the filtering characteristic can be adjusted by changing the capacity value. The structure can be reconfigurable with the adjustments made on the main transmission line of the structure, allowing the transition of the structure from the band-pass filtering characteristic to the band-stop filtering characteristic. Moreover, by increasing the capacity value the frequency response can be also switched from single mode to dual mode. The simulations in this study were performed with the help of

International Journal of RF and Microwave Computer‐Aided Engineering, 2021

In this paper, practical fuzzy models depending on subtractive fuzzy clustering have been present... more In this paper, practical fuzzy models depending on subtractive fuzzy clustering have been presented for asymmetrical V‐shaped microshield line. In addition, a packet program has been introduced to run the proposed fuzzy models. In order to calculate the electrical parameters of each model, a linear equation system has been formed in each fuzzy model. Finally, the coefficients of each equation system have been found by means of fuzzy rules obtained by cluster extraction. The accuracy of each model has been confirmed by error analysis and the validity of the model results has been proven by comparing with the results of the quasi‐static approach. At last, an object‐oriented package program including theoretical solutions and fuzzy modeling has been presented. This computer‐aided design program can be used for analysis, synthesis and modeling of transmission lines and microwave filters. It has been developed to calculate design processes with high speed and accuracy for researchers. It...

2019 49th European Microwave Conference (EuMC), 2019

2016 46th European Microwave Conference (EuMC), 2016

Design of a microstrip narrowband bandpass filter with bandwidth tunability and reconfigurability... more Design of a microstrip narrowband bandpass filter with bandwidth tunability and reconfigurability is presented in this paper. For this purpose, patch reference elements and a varactor diode as tuning element are used to excite the degenerate modes of a dual-mode square loop resonator. Even/odd mode resonance conditions of the proposed filter are expressed to define the locations of mode frequencies. According to the capacitance of the varactor diode, bandwidth tuning for linear phase/quasi elliptical filtering characteristics and band rejection can be achieved. A microstrip bandpass filter having tunable bandwidth and reconfigurable filtering characteristics is fabricated and measured for the experimental verification of the proposed method.