Robustness study of bandpass NGD behavior of ring-stub microstrip circuit under temperature variation

This paper explores an original study of bandpass (BP) negative group delay (NGD) robustness applied to the ring-stub passive circuit. The proof of concept (PoC) circuit is constituted by a ring associated with the open-end stub implemented in microstrip technology. An innovative experimental setup of a temperature room containing the NGD PoC connected to a vector network analyzer is described. Then, the electrothermal data of S-parameters are measured by varying the ambient or room temperature range from 20 to 60°C, i.e. 40°C maximal variation. The empirical results of the group delay (GD), transmission and reflection coefficient mappings versus the couple (temperature, frequency) highlight how the temperature affects the BP NGD responses. An innovative electrothermal calibration technique by taking into account the interconnection cable influence is developed. The electrothermal robustness analysis is carried out by variations of the NGD center frequency, cut-off frequencies and value in function of the temperature.

A Microstrip Low-Pass Filter Design Using a Modified Radial Resonator in the Application of Aircraft Distance Measurement Equipment

In this paper, the application of microstrip technology is investigated in low-pass filters. A cascade microstrip low-pass filter with a sharp frequency response and a good cut-off bandwidth is presented using a modified radial resonator. The advantages of this proposed filter include minor losses in the transit band as well as the desired return. This filter design shows consistency when compared with the results of simulation and model performance. A comparison between the parameter values of this filter and previous structures indicates that it is desirable. The proposed filter can be used in modern communication systems such as aircraft distance measurement equipment (DME) antenna.

A Step-by-Step Approach to Bandpass/Channel Filter Design

This paper presents a step-by-step approach to the design of bandpass/channel filters. The chapter serves as a reference source to microwave stakeholders with little or no filter design experience. It should help them design and implement their first filter device using the microstrip technology. A 3-pole Chebyshev bandpass filter (BPF) with centre frequency of 2.6 GHz, fractional bandwidth of 3%, passband ripple of 0.04321 dB, and return loss of 20 dB has been designed, implemented, and simulated. The designed filter implementation is based on the Rogers RT/Duroid 6010LM substrate with a 10.7 dielectric constant and 1.27 mm thickness. The circuit model and microstrip layout results of the BPF are presented and show good agreement. The microstrip layout simulation results show that a less than 1.8 dB minimum insertion loss and a greater than 25 dB in-band return loss were achieved. The overall device size of the BPF is 18.0 mm by 10.7 mm, which is equivalent to 0.16λg x 0.09λg, where λg is the guided wavelength of the 50 Ohm microstrip line at the filter centre frequency.

Interdigital Coupled Compact FSS Reflector for UWB Antenna Gain Enhancement

A compact UWB FSS reflector is presented based on interdigital structure for gain enhancement of an UWB antenna. An equivalent circuit approach is proposed for the analysis of the FSS reflector. The reflector comprises a 6 × 6 array of unit cell dimension 6 mm × 6 mm and which is very compact. The reflector gives a linear phase response over UWB band. A UWB monopole antenna is designed with a half circular disc structure based on microstrip technology. A maximum of 5 dBi gain enhancement is achieved with this compact FSS reflector when placed at a distance below the antenna. The measured results closely follow the simulated ones which proves feasibility of this design.

Multiband Triple L-Arms Patch Antenna with Diamond Slot Ground for 5G Applications

This paper reported a pioneering 5G multiband microstrip line fed patch antenna for IoT, wireless power transfer (WPT) and data transmission. The proposed antenna is accomplished using a triple L-arms patch antenna responsible for the multiband response. A diamond-shaped ground slot is added to control and increase the bandwidth of the resonant frequency. The antenna is designed to resonate at 10, 13, 17 and 26 GHz with 10 dB impedance bandwidths of 0.67, 0.8, 2.45 and 4.3 GHz respectively. The proposed antenna is fabricated using microstrip technology with total area of 16.5x16.5 mm2. The 5G multiband antenna has sufficient realized gain of 4.95, 5.72, 4.94 and 7.077 dB respectively. The antenna is designed and simulated using the CST Microwave Studio Suite (Computer Simulation Technology). Measurements show good agreement with simulations in all frequencies of operation.

Compact Low-Cost Filter for 5G Interference Reduction in UHF Broadcasting Band

The allocation of part of the UHF band to 4G and 5G services has generated the appearance of channel interferences over the digital terrestrial television frequency band. In order to reduce these interferences, this work presents a novel and efficient band-stop filter implemented using microstrip technology. The filter, designed with rectangular split-ring resonators etched in the ground plane, provides a cutoff frequency above channel 48 (694 MHz), a high roll-off rate of 44 dB in 56 MHz and a rejection bandwidth of 250 MHz that covers the upper UHF band occupied by 4G and 5G with rejection levels close to 35 dB. The filter is manufactured entirely over a printed circuit board without lumped elements to reduce production costs, fine tuning after the assembly stage and maintenance. Moreover, it presents a compact subwavelength size of only 0.07 λ × 0.17 λ to facilitate installation, whether at the input of the TV terminal or integrated with the balun at the rooftop antenna.

Passive Equalization Networks—Efficient Synthesis Approach for High-Speed Signal Integrity Characterization

High data rates challenges and long traces from current state-of-the-art systems imply high attenuation. In the present article, we will present a detailed process of synthesis of equalizers, for choosing the correct one for a given application. The methods are based on scattering parameters applied on interconnections modeled as microstrip or stripline. Firstly, one may have an overview of types of equalizers, passive, active, and adaptive ones, and a detailed filter synthesis is applied in microwave systems having as start point the insertion loss of a given trace on a given substrate. Next, time domain analyses offer a better understanding of the performance of the interconnect, based on eye diagram inspection and the variation of waveforms with time. Finally, we will present results based on simulation of the equalizers network in a microstrip technology followed by discussions and conclusions. The study proposes to use equalizers in either the transmitter or receiver point, proposes a bridge equalizer with the cost of additional elements but improved constant input, output impedance, and also a new variant for single ended trace based on microwave resonator is proposed. Performance is demonstrated by results from simulations.

Chaos generator with high energy potential

An original scheme is proposed for generator of chaos oscillations of the microwave wavelength range. Generator contains nonlinear positive feedback amplifieran and inertial converter of the output signal of a nonlinear amplifier, the signal of which modulates the supply voltage of the active element (transistor). In the case when the value of the inertia parameter of the inertial converter becomes less than 0,06, the generator demonstrated chaotic behavior. An experimental model of a chaotic signal generator based on a powerful transistor 2T982A-2 was created. The generator was created using hybrid microstrip technology on the material FLAN-10 with a thickness of 1 mm. The inertial converter circuit contained a diode performing half-wave conversion of a part of the generator output signal and an RC circuit with a time constant equal to 0,05 of the time one oscillation at the central frequency of the generator. The signal from the output of the inertial converter was applied to the emitter power supply circuit of the transistor. Modulation of the supply voltage led to the fact that the output signal of the generator was a sequence of non-repeating oscillation trains with a random duration and a random initial phase. The frequency band of the generated chaos with an uneven power spectrum of 4 dB occupied a frequency range from 3,1 to 3,3 GHz with an integrated power of 1,2 W. The averaged spectral density of noise oscillations was 6 10-3 W/MHz. Generator efficiency 15%.