Periodically loaded waveguide structures

The purpose of this paper is to investigate a novel class of waveguide resonator structures using periodic metal septa for use at microwave, mm-wave, submm-wave and terahertz frequencies. Its aim is to show that this type of resonator can be easily realized with a single metal insert within circular, ridged and rectangular waveguide. One type of resonator which used quarter-wavelength metallic septa was employed. The simulated results for air-filled metal pipe rectangular and ridged waveguide resonator and filter structures using periodic metallic septa are presented

Efficient Neural Network DPD architecture for Hybrid Beamforming mMIMO

This paper presents several different Neural Network based DPD architectures for hybrid beamforming (HBF) mMIMO applications. They are formulated, tested and compared based on their ability to compensate nonlinear distortion of power amplifiers in a single user (SU) and multiuser (MU) Fully‐Connected (FC) HBF mMIMO transmitters. The proof‐of‐concept is provided with a 64 × 64 FC HBF mMIMO system, with 2 RF chains. The complexity of DPD solution is reduced by using a single Real‐Valued Time‐Delay Neural Network with two hidden layers (RVTDNN2L) instead of using as many different DPD blocks as there are RF chains in the HBF mMIMO transmitter and it is shown that the proposed architecture better compensates nonlinear distortion compared to the traditional memory polynomial DPD. Two RVTDNN2L DPD architectures are developed and tested for linearization of MU FC HBF mMIMO systems, and it is also shown that the proposed RVTDNN2L DPD architecture efficiently linearizes MU FC HBF mMIMO transmitters in terms of Normalized Mean‐Squared Error (NMSE) and Error Vector Magnitude (EVM)

Microstrip three-port 4-channel multiplexers using dual-band bandpass filters for wireless applications

This paper presents a compact microstrip three-port 4-channel multiplexer using dual-band bandpass filters with good transmission and reflection characteristics on each channel. Proposed multiplexer configuration can be used for design of very compact multiplexer for broadband wireless applications using super compact microstrip pseudo-interdigital quasi-elliptical bandpass filters with or without stepped impedance resonators. The size of the proposed circuit is reduced. The improvement of the performance of multiplexer through introduction of additional transmission zeros is under investigation

An optically reconfigurable dual-band branch-line coupler with artificial transmission lines

This paper demonstrates switches that achieved a frequency shift of 30% from all switches off to all switches on in both frequency bands. This study shows the advantages of this approach such as high-speed switching, electromagnetic transparency, and thermal and electrical isolation between the coupler and the control circuit. The use of the artificial transmission lines significantly decreases the overall size of the circuit

Dual-band Filtenna Array for WLAN Applications

This paper presents the design and results of a dual-band antenna array integrated with bandpass filters for WLAN applications. The array is fed with a single 50 Ω port and consists of two radiating elements; thereby having a 1x2 array structure. The two bands of the antenna array correspond to the two WLAN bands of 2.4 GHz and 5.8 GHz. A standalone array has first been designed. Other than the two fundamental resonant frequencies, the standalone array exhibits spurious harmonics at various other frequencies. For the suppression of these harmonics, the array has been integrated with two bandpass filters, centered at 2.4 GHz and 5.8 GHz. The resulting filtenna array was simulated, fabricated and measured. Obtained simulation and measurement results agree well with each other and have been presented to validate the accuracy of the proposed structure. Measured return loss of the structure shows dual-bands at 2.4 GHz and 5.8 GHz of more than 30 dB each and also a successful suppression of the spurious harmonics of the antenna array has been achieved. Radiation patterns have also been simulated and measured and both results shown. The gain and efficiency have also been presented; with the values being 6.7 dBi and 70% for the 2.4 GHz band and 7.4 dBi and 81% for the 5.8 GHz band respectively

Dual-band WLAN Antenna Array with Integrated Bandpass Filters for Harmonic Suppression

This paper presents the design and results of a dual-band antenna array integrated with bandpass filters. The array has a 1×2 configuration. The two bands of the array correspond to the two WLAN bands of 2.4 GHz and 5.8 GHz. Other than the two main bands, the standalone array exhibits spurious harmonics at various other frequencies. For the suppression of these harmonics, the array is integrated with two bandpass filters, centered at 2.4 GHz and 5.8 GHz. The filtering array was simulated and fabricated. Measured results show dual-bands at 2.4 GHz and 5.8 GHz at a return loss of more than 30 dB and also a successful full suppression of the spurious harmonic

Evaluation of Waveform Candidates for 5G Wireless Communications

In this paper, we evaluate the waveform candidates for 5G wireless communications such as FBMC and UFMC and 4G’s cyclic prefix CP-OFDM. Measured results for 1.4 MHz and 3 MHz waveforms show a 5 dB reduction in ACPR between FBMC and UFMC. Simulation and measured output power spectra of the power amplifier for 3 MHz and 10 MHz waveforms are match very well

Dual-band WLAN Antenna Array with Integrated Filters for Harmonic Suppression

This paper presents the design, modelling and results of a dual-band antenna array integrated with filters. The array is fed via a single 50 Ω port and consists of two radiating elements. Hence, a 1x2 array structure. The two bands of the antenna array correspond to the two WLAN bands of 2.4 GHz and 5.8 GHz. Other than the two fundamental resonant frequencies, the standalone array has spurious harmonics at various other frequencies. For the suppression of these harmonics, the array is integrated with two bandpass filters, centered at 2.4 GHz and 5.8 GHz. The antenna array with integrated filters was electromagnetically modelled and the simulation results have been presented. The acquired results are considerably acceptable; showing the array to have dual-bands at 2.4 GHz and 5.8 GHz, at a return loss of more than 20 dB, and also successful suppression of the spurious harmonics of the antenna array

Compact Inline E plane Waveguide Resonators and Bandpass Filters with I-shaped Resonant Insets

In this paper, waveguide resonators and bandpass filters with E-plane inserts containing I-shaped resonant insets are presented. These insets introduce to the response finite transmission zeros much less sensitive than those produced by cross-couplings. Also, their use results in structure compactness, unlike bandstop resonant cavities that add volume. Two kinds of extracted pole sections that demonstrate response flexibility of the proposed resonators are designed at 10 GHz and tested. One is based on the dominant mode with a transmission zero in the upper stopband and the other on a pair of higher order modes with a transmission zero in the lower stopband. Also, a 3rd order filter for 11 GHz band combining both dominant and higher order mode resonators is modeled to illustrate the scalability of such a modular design. These filters are very suitable for low-cost mass production

Compact multilayer SRR-loaded integrated waveguide filters on liquid crystal polymer substrate

This article presents a compact bandpass filters based on rectangular substrate integrated waveguides and split ring resonators for implementation in multilayer LCP technology were proposed. Filter which included two sections of E-resonator and SRR was tuned up to central frequency of about 28 GHz and bandwidth of about 2 GHz