Realization of Ku-Band Ortho Mode Transducer With High Port to Port Isolation

Abstract

Abstract-Present paper describes the design, development and evaluation of a wideband, compact Ku-band orthomode transducer (OMT) for SATCOM application. It consists of a square waveguide output section, square waveguide to rectangular waveguide transition, straight waveguide port and an orthogonally coupled port. A tapered waveguide section has been used to couple the orthogonal RF (Radio Frequency) signal to the common port. The designed OMT has a transmit port with frequency band 13.75 GHz-14.5 GHz and a receive port with frequency band 10.95-12.5 GHz. Finite element method based ANSYS's High Frequency Structure Simulator (HFSS) EM software has been used for simulation and optimization of OMT. Measured reflection coefficients of OMT over transmission and reception frequency bands are better than −15 dB and −12 dB, respectively. Designed OMT has port to port isolation better than 45 dB against 30 dB isolation of conventional OMT available in market.

3-D Printed Antenna Subsystem With Dual-Polarization and its Test in System Level for Radiometer Applications

“…Lengths of the square waveguide section and the tapered waveguide section are L2 and L3, respectively. A mode-matching technique is utilized in the tapered waveguide to reduce transmission loss for each port [25]. The signals are coupled to the coupling port through a coupling aperture.…”

An x‐band waveguide orthomode transducer with integrated filters

“…Conventionally, filtering elements in the branches are designed independently followed by the construction of the T‐junction . The T‐junctions are usually analyzed and modeled using the equivalent circuits .…”

“…In Reference , the T‐junction is analyzed and represented by the equivalent lumped circuit having complex loads, and then the filters are added to provide matching . The parametric analysis is performed to determine the T‐junction structure in Reference . In Reference , a filter is only added to the vertical polarized port, with the other port directly coupled to the waveguide.…”

“…Conventionally, filtering elements in the branches are designed independently followed by the construction of the T-junction. [5][6][7][8] The T-junctions are usually analyzed and modeled using the equivalent circuits. 5,6 In Reference 6, the T-junction is analyzed and represented by the equivalent lumped circuit having complex loads, and then the filters are added to provide matching.…”

Multi‐frequency dual polarisation radiometer common aperture antenna feeding system

“…The band-pass filter (BPF) and high-pass filter (HPF) are used to separate microwaves of different frequencies. The different BPFs and HPFs can work together to make sure that the needed waves are selected [13][14][15][16]. Besides the tri-band performance, low voltage standing-wave ratio (VSWR), low cross-polarisation level and symmetrical patterns are needed to achieve through this feeding network, typically technical specifications such as VSWR < 1.5, cross-polarisation level<−20 dB, SLLs<−20 dB are minimum standards for radiometer antenna (with dish if necessary) within the working frequency band.…”