Coupling Branch Research Articles

W-Band Beam-Tilted H-Plane Horn Array Antenna with Wideband Integrated Waveguide Feed Network Based on MMPTE

A W-band H-plane horn array antenna with tilted radiation beam based on waveguide structure is proposed in this paper. The designed antenna array consists of four H-plane antenna elements and a broadband feed network. The distribution of excitations is determined by the theory of maximum power transmission efficiency (MMPTE). A multiple branch coupler, two T-junctions and three fixed phase shifters are employed to construct the feed network, which can generate the required amplitude and phase in broadband frequency range from 80 GHz to 100 GHz. The computer numerical control (CNC) milling machines technology is employed to machine the feed network and antenna. All measured and simulated results are in good agreement, which verify the feasibility of the theory of MMPTE to generate a radiation beam directed to any angle from -35° to 35° with suitable excitation provided by the proposed feed network in this paper.

Design of a full V‐band fundamental mixer with an ultra‐wide IF from 0.01 to 22 GHz

Design of a low cost Schottky diode based single-balanced mixer (SBM) in full V-band with an ultra-wide intermediate frequency (IF) bandwidth is presented here. By loading multiple quarter-wavelength short-ended stubs at both radio frequency (RF) and local oscillator (LO) frequency on the multistage stepped impedance matching networks, a broadband grounding circuit is provided for IF signal and thus output power nulls are eliminated over an ultra-wide IF band. The hybrid network is constructed by a 3 dB branch coupler and a 90-degree delay line, which enables the required balanced outputs with equal amplitude and 180-degree phase difference. A prototype of the SBM is designed, fabricated and tested. Measured results demonstrate that, for RF and LO frequency over entire V-band, the mixer has a conversion loss from 6.8 to 11.4 dB with an ultra-wide IF range of 0.01–22 GHz.

A new circular polarization dual feed microstrip square patch antenna using branch coupler feeds for WLAN/HIPERLAN applications

Abstract Microstrip patch antennas represent one family of compact antennas that offer a conformal nature and the capability of ready integration with communication system’s printed circuitry. In this paper, a 5.4 GHz circular polarization microstrip antenna is designed and simulated. The selected microstrip antenna is a dual-fed circular polarized microstrip antenna. The antenna consists of miniaturization square patch and 3dB hybrid coupler. The array antenna can excite both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) with using hybrid coupler is directly connected to microstrip antenna to get circular polarization. Circular polarization is obtained when two orthogonal modes are equally excited with 90° phase difference between them. Circular polarization is important because regardless of the receiver orientation, it will always be receiving a component of the signal. This is due to the resulting wave having an angular variation. Simulation results shows that the designed antenna characteristic is suitable for WLAN/HIPERLAN wireless applications.

A Low-loss Phase Shifter with Harmonics Suppression Using Compact Hybrid Coupler

In this paper, a compact low-loss reflector-type phase shifter with harmonic suppression using meander T-shaped branch-line coupler is suggested. The compact coupler for the phase shifter has a size of while a conventional branch coupler has a size of . The phase shifter shows insertion losses of 0.19-0.28 dB at the center frequency of 2.1 GHz, and a measured maximum phase shift of .

Si wire waveguide wavelength filter using asymmetric width waveguide branch coupler and Bragg grating

The design for a Si wire waveguide wavelength filter using Bragg grating and a coupler composed of branching asymmetric width waveguides is reported. The coupler is tolerant against waveguide width deviation and shows wide working wavelength range. The device is designed for optical network units used in fibre to the home systems.

Computer-aided design, analysis and optimization of HMIC SOP broadband balanced amplifier

The purpose of this paper is to present a complete design and analysis of new HMIC 3.5-4.5 GHz broadband balanced amplifier modules using microstrip technology. Two different modules are designed and analyzed. Each module is implemented in a single substrate. The first module used Lange couplers as power splitters and combiners while the second used branch couplers. The components of the modules are designed using full-scale computer simulation program, performed by the author and named as MSDES, which takes fully into account all the discontinuities included in the microstrip lines; while the modules are analyzed and optimized using APLAC V7.61 software. A short and efficient CAD procedure for the broadband amplifier design is introduced. The first step is to design an initial narrowband high-gain microstrip amplifier at a center frequency equal to 4 GHz. The second step is to optimize the initial lengths and widths of the input and output microstrip-matching circuits to get the broadband amplifier over the range 3.5-4.5 GHz. The analyses of both narrow and broadband amplifiers are introduced in addition to the complete analysis of the designed 3.5-4.5 broadband balanced amplifier modules. The analysis of the designed balanced amplifier modules shows better efficiency and good performance. The complete AC schematic diagrams of the designed balanced amplifier modules are presented. These modules can be used in many applications including sensors, pulse Doppler communications, airborne radars, traffic control radars and satellite communications.

Assembly of Silica Nanowires on Silica Aerogels for Microphotonic Devices

We report on the assembly of low-loss silica nanowires into functional microphotonics devices on a low-index nondissipative silica aerogel substrate. Using this all-silica technique, we fabricated linear waveguides, waveguide bends, and branch couplers. The devices are significantly smaller than existing comparable devices and have low optical loss, indicating that the all-silica technique presented here has great potential for future applications in optical communication, optical sensing, and high-density optical integration.

Waveguide branch couplers for tight couplings

Full-wave optimization design of waveguide branch couplers is presented. Waveguide T-junction equivalent circuit parameters are extracted from full-wave modeling results. They are used to explain why tight couplings are difficult to realize using waveguide branch couplers. Approaches used to obtain tight couplings are discussed and illustrated by two design examples of 3-dB couplers. Through random tolerance analysis, it is found that reasonable manufacturing tolerances have no significant effect on coupler performance.

An analysis of wave patterns in multiport quantum waveguide structures

Wave patterns in two- and four-port quantum waveguide structures are reported in order to analyse the operating modes of T-stub, single-branch and double-branch quantum couplers. The ballistic transport study is carried out using mode-matching techniques for solving the two-dimensional Schrödinger equation and special attention is paid to density probability and phase variations. To understand how carrier streams are driven towards the output ports, the local density of states and scattering parameters are calculated. On this basis, various geometries are considered and their operating modes including energy filtering in T-stub structures, real space transfers in a single-branch coupler and 3 dB coupling in a double branch coupler are investigated. We distinguish between operating mechanisms relying on multimode propagation and on interference processes in the monomode regime in order to investigate the origin of the directivity.

Effects of amplitude, phase, and frequency imperfections on the performance of a direct conversion receiver (DCR) for personal communication systems

Results from a practical study of a direct conversion receiver (DCR) and its subsections, namely, power splitter, branch coupler hybrid, coupled lines bandpass filter, lowpass filter, balanced mixer, and oscillator, are presented. The receiver is designed for the 2-GHz frequency band, with particular reference to personal communications terminals for the digital European cordless telecommunications (DECT) standard. The DCR overall performance, based on measured figures of individual subcircuits, is analyzed with the aid of the Eesof-Omnisys simulator. Typical value for the signal-to-noise ratio is 12 dBm for 10/sup -3/ bit-error rate. The receiver can tolerate amplitude and phase mismatches of 3% and 5 degrees , respectively, as well as 1.2-kHz local oscillator drift. The dynamic range is 80 dB. The performance of the DCR fits well with the DECT specification.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fiber coupling using graded-index rod lenses

The graded-index rod lens (GRIN lens) is useful in coupling between multimode optical fibers. Applications include connectors, switches, multiplexers, and branch couplers. In these devices, one GRIN lens collimates light from an input fiber, and a second lens collects the light and focuses it on an output fiber. This paper presents analyses of power losses in these devices resulting from lateral and angular misalignments and from the spacing between the lenses. It is found that the GRIN lens coupling system is very sensitive to angular alignment but is more tolerant of lateral errors and lens spacing.

A Directional Coupler with Very Flat Coupling

A reciprocal 4-port device is a directional coupler if any input port is matched and the device possesses either 180/spl deg/ rotational symmetry about two perpendicular axes, or 180/spl deg/ rotational symmetry about an axis combined with reflection symmetry in a plane either containing or perpendicular to the axis. In this paper an expression is derived for the equivalent admittance of such a device considered as a directional coupler. This expression is used to determine the equivalent admittance of the simplest symmetrical 2 branch coupler. Furthermore, it is shown that the coupling must be the same for all frequencies for which this junction is matched by identical 2-port matching networks connected at each port. These facts were used to build a 90/spl deg/ hybrid in stripline with maximum power division unbalance of 0.05 dB over the 3.7- to 4.2-GHz band.

A Method for Accurate Design of a Broad-Band Multibranch Waveguide Coupler

A new approach is made to the problem of tapering the branch impedances for broad-band performance. A taper is proposed, which, for a 3-db branch coupler, is shown to give much better results in theory and practice than the currently used binomial taper. Also, simple expressions are developed which enable the effects of waveguide junction discontinuities to be adequately corrected, thus allowing a greater accuracy in design to be achieved than was hitherto possible.