Reflective interference caused by impedance discontinuities in the interconnect is a serious impediment to high speed serial link designs. The reflections can be addressed either through expensive equalization circuits or through interconnect redesign. Here a new technique for determining the most significant places to make changes in an interconnect design is presented. Through linearizing the S-parameter cascading process three unique reflection budgets are created based on 1) frequency domain insertion loss deviation, 2) time domain peak distortion analysis and 3) time domain reflectometry. Example analysis of a 25.8 Gb/s NRZ system identifies the connectors as the primary contributors to reflective interference and estimates that the interactions with the rest of the interconnect with the connector impedance discontinuities reduces the system eye height by 84 mV.....

A low-profile compact uni-planar slot antenna design of size 26 mm × 26 mm is proposed, assisted with a metallic bottom reflector at a height of λ/6 (λ is the lowest CP frequency). The dual-band dual-polarization is observed at 6.2 GHz and 9.3 GHz, and polarization sense (LHCP and RHCP) is dynamically switched by introducing a pair of RF p-i-n diodes mounted at the confluence of right-slot (RS) and left-slot (LS). The metallic reflector of size 60 mm × 60 mm helps to improve overall impedance matching, enhance antenna gain and asserts uni-directional dual-polarized radiation with good back-lobe suppression. The proposed antenna operates at dual bands (5.46-6.76 GHz) with 21.27% IBW and (8.18-10.48 GHz) with 24.65% IBW for S₁₁ < -10 dB. The antenna gain reaches (7.82-8.75 dBi) for D1-OFF, D2-ON state with (9.2%, 15.63%) axial bandwidths and (6.42-7.0 dBi) for D1-ON, D2-OFF state with (7.53%, 16.04%) axial bandwidths with radiation efficiency ranging (75-87%). A prototype antenna is fabricated and measured, which shows good agreements with simulated performances and can be used for sub-6 GHz in 5G applications and X-band radar systems.....

An investigation on using eco-friendly natural materials like coconut pith, rubber and charcoal powder for developing radio wave absorbers has been reported in this paper. Two absorbers named CoR (Combination of Coconut pith powder and natural Rubber latex) and CoRC (Combination of Coconut pith powder, natural Rubber latex and Charcoal powder) are made through proper mixing and drying. The absorptivity of these two absorbers (CoR and CoRC) is compared with the industrial standard polyurethane based absorber. The waveguide method is employed to measure the absorptivity of these absorbers in 3 different frequency bands. Band 1 (1.7-2.6 GHz) includes the mobile communication frequencies of 1.8 GHz and 2.4 GHz. Band 2 (4.9-7.05 GHz) is intended for sub 6 GHz band of 5G as well as WLAN frequencies while band 3 (8.2-12 GHz) is for higher frequencies of radar operation. The exact values of lower and upper frequencies of bands are determined by the physical dimensions of waveguides used. The absorption capability of the absorbers is found to increase as the frequency of operation increases. The CoR absorber has almost 63% average absorptivity in band 3, 56% in band 2 and 21% in band 1. The CoRC absorber has an average of 74% absorptivity in band 3, 63% in band 2 and 24% in band 1.....

This letter shows a compact planar microstrip crossover. The crossover design employs a microstrip to coplanar waveguide transition. The crossover is fabricated on a low cost and readily available FR-4 substrate, and simulation and measurement responses in the low frequency band have been shown. The number of GND vias forming a quasi-coaxial section that confined the electric field around the signal via was increased to improve impedance matching. The core size of the circuit is as compact as 20 mm × 10 mm even in the low frequency band. The crossover operates in the low frequency band with insertion loss of less than 1 dB, return loss of more than 10 dB, and isolation of more than 15 dB.....