Erdem Demircioglu

S-band TCR patch antenna design for nano satellites

The small satellites offer reduced cost and low mass solutions for various mission needs such as Earth monitoring, scientific experiments, and data communication. Thus the small satellite market grows proportionally as their developing technologies replace the operations of conventional large satellites. Nowadays manufacturers consider small satellites due to their reduced time scale during design and integration phases. In this trend, light weight, reliable antennas with wide radiation patterns and adequate gains have to be employed in small satellites to accomplish telemetry, command, ranging (TCR) functions and high speed payload data transmission. In this study, an S-Band patch antenna design procedure is examined in order to meet the TCR functional requirements in nano satellites. The proposed patch antenna can be utilized for the payload transmission which includes the amateur radio applications and earth monitoring.

Determination of communication satellite orbit over navigation systems

Determination of communication satellite orbital parameters via accurate measurements plays a vital role to control satellites in a sturdily way. The anomalies occurred in satellite orbit must be determined in time to keep it in its nominal orbit using on-board active control systems such as thrusters. In this study, utilization of a Ku-band navigation system for satellite orbital parameter determination is examined. The navigation signals are transmitted from Turksat communication satellite over its wide coverage areas.

A planar Ku band antenna for satellite communications

In this study a planar Ku band antenna is designed and built for satellite communications especially to receive TV signals in Turkey. This paper summarizes the design and manufacturing phases of the study and demonstrates the simulation results of the prototype antenna.

GNSS augmentation and regional positioning systems over Turksat communication satellites

Traditional GNSS positioning systems utilize MEO constellation of satellites with composite ranging signals. However these systems have major drawbacks of high manufacturing cost, operational difficulties and lack of performance during all time usage. These drawbacks force to find alternative methods for improving positioning accuracy. In this paper, a regional positioning system and the satellite based augmentation system (SBAS) over Turksat GEO satellites are investigated. The proposed systems are operating over Ku-band DVB signals instead of traditional L-band ones. Systems are active for end users inside the communication satellite coverage areas.

Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs) using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN). To achieve the best ANN performance, Particle Swarm Optimization (PSO) and Differential Evolution (DE) are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

A novel microstrip patch antenna design for mobile applications

In this study, a microstrip antenna operating at 1840 MHz is designed and simulation results are presented. Sonnet Suits 12.56 a powerful 3D EM simulator for antenna applications is utilized as the design software. The antenna air thickness is 170 mm and the gap between the antenna and floor is 3.05 mm. Cell size is regarded as 0.75 mm. The frequency of antenna is simulated in the frequency range of 1-3 GHz. S11, the back scattering parameter has the value of -15.5434 dB at the center frequency. The real value of the input impedance is 38.23716 Ohms and the imaginary value is 9.008487 Ohms. The resonance frequency has the gain value of 8.883196 dB.