Antipodal Finline Research Articles

Study on Transmission Characteristics in Three Kinds of Deformed Finlines Based on Edge-Based Finite Element Method

Abstract The influence of model deformation on the transmission characteristics in unilateral finline, antipodal finline and bilateral finline is discussed using edge-based finite element method (FEM). The deformation is considered with respect to the eight boundaries of the model, and their amplitude is set to 0.01–0.05; the transmission characteristics include the cutoff wavelength characteristics of the dominant mode and the single-mode bandwidth characteristics. The results show a decreasing trend when the vacuum area is deformed, while they show a variety of possibilities when the loading region is deformed. These numerical results have strong guiding significance for the influence of the deformation of finlines on the overall device.

Compact low‐loss millimeter‐wave shielded asymmetrical coplanar stripline to unilateral and antipodal finline transitions

Compact and low-loss U-band shielded asymmetrical coplanar stripline (SACPS) to unilateral and antipodal finline transitions are proposed in this article for millimeter-wave circuits and systems applications. The principles of mode conversion and impedance matching are applied to the proposed transitions. In the SACPS to unilateral finline transition, the SACPS is firstly transformed into the asymmetrical unilateral finline to convert the quasi-TEM mode to the quasi-TE10 mode and then a tapered unilateral finline section is applied to realize impedance matching. For the U-band back-to-back SACPS to unilateral finline transition, the measured return loss is larger than 15 dB and the insertion loss is less than 1.5 dB with a minimum of 0.5 dB. In the SACPS to antipodal finline transition, the SACPS is firstly transformed into the defected ground microstrip (DGM) without changing the characteristic impedance. Then, the DGM is transformed into the asymmetrical antipodal finline to make mode conversion. At last, a tapered antipodal finline section is used for impedance matching. For the U-band back-to-back SACPS to antipodal finline transition, the measured return loss is larger than 12 dB and the insertion loss is less than 1.5 dB with a minimum of 0.3 dB.

Waveguide Planar E-plane Filter with Ultra-Wide Stopband

A waveguide planar bandpass filter for 2-cm wavelength range (13.5–14.5 GHz) with an ultra-wide stopband (up to the 6th harmonic of the central frequency of the bandwidth) is proposed, developed and experimentally investigated in this article. The filter with a bandwidth is designed on the basis of the antipodal fin-line (AFL) with an extremely high overlap of ridges, which has an overlap size to a waveguide height ratio is equal to 0.773. It allows to significantly reduce the cross-section of the filter waveguide chamber. The compact waveguide planar transformers located on the same substrate are used as the input and output transformers of the filter. It excludes the influence of inaccuracy in the filter structure adjustment relative to the joints with the supply waveguides. Despite the smallness of the resonators longitudinal dimensions in comparison with the half-wavelength in a AFL, the filter synthesis with an acceptable for practice accuracy can be carried out according to Cohn method, modified for its specified feature. At the same time, the decrease in the filter resonators’ intrinsic Q-factor, associated with a strong overlap of the AFL ridges, leads to dimension correction. However, this correction is performed in one of the common program packages of electrodynamic analysis based on the measuring results of the filter resonators’ intrinsic Q-factor.

W-band Downconversion Mixer with Finline Transition for Intelligent Traffic System

A W-band MMIC mixer using 0.15-㎛ T-gate GaAs pHEMT technology is presented. The proposed mixer is designed as a single balanced diode mixer type with schottky barrier diode and implemented with finline transition for 77-㎓ intelligent traffic system(ITS) transceiver(TRx) module. The mixer also includes an IF amplifier to increase a conversion gain, and the waveguide-to-microstrip antipodal finline transition is designed with cosine-squared taper function curve and fabricated with duroid 5880 substrate. The optimized finline transition shows the measured insertion loss of less than 1㏈ and the return loss of higher than 20㏈ for 77㎓. The measured conversion gain of the proposed W-band mixer is 0.3㏈ at LO power of 11㏈m, which satisfies the mixer specification for ITS automotive collision avoidance radar receiver module.

A Design Approach for Tapered Waveguide to Substrate-Integrated Waveguide Transitions

A design approach for substrate-integrated waveguide (SIW) to rectangular waveguide (RWG) transitions based on the synthesis of antipodal finline tapers is proposed. The taper is designed using a reflection-based impedance definition as no suitable model is available for antipodal finlines. The characteristics of the finline are determined from full-wave simulation. To demonstrate the proposed method, two SIW-to-RWG transitions are designed and characterized at the $K$ -band. The measured back-to-back transitions exhibit a return loss above 15 dB and an insertion loss below 1 dB between 16.7 and 20.5 GHz and between 21.1 and more than 31 GHz, respectively. A good agreement between the synthesis model and full-wave simulation of the taper on one hand and between simulation and measurements of back-to-back transitions on the other hand is demonstrated.

Low loss and broadband transition between substrate integrated waveguide and rectangular waveguide

In this article, a novel transition between substrate integrated waveguide (SIW) and rectangular waveguide is proposed. A pair of antipodal tapered probes is developed to convert the E-field of SIW to that of waveguide, acting as an antipodal dipole antenna to improve the performance of the SIW-to-waveguide transition. A back-to-back prototype of the proposed transition is fabricated and measured, the results show that the transition achieve a bandwidth of 51.1% from 23.7 to 40 GHz, and a size reduction of 75.3% compared to the SIW-to-waveguide transition using antipodal fin-line. A tolerance analysis is performed via the simulation to verify the reliability of this transition design. For further validation, the antipodal tapered probes are employed for the design of partially filled SIW-to-waveguide transition. From its experimental results, it demonstrates that the loss of a single SIW-to-waveguide is less than 0.26 dB over the frequency range of 24.9–40 GHz. In addition, such proposed SIW-to-waveguide transition is suitable for hermetic packaging due to the inherent property in transition structure. These results show that the proposed transition can offer the advantages of broad bandwidth, low loss, compact size, and stable performance at millimeter-wave frequencies. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:54–61, 2016.

5세대 이동통신 시스템을 위한 도파관-마이크로스트립 앤티포달 변환에 관한 연구

In this paper we characterized and designed the waveguide antipodal finline transition at 57-65GHz frequency band in V-band for 5G mobile communication systems. Especially, we proposed the design method of spline taper for finline tapers by means of increasing curvature from linear taper. We could perform optimization more effectively by excluding improper regions for optimal performance from optimization using the method. Return losses and insertion losses of antipodal finline transitions were mainly affected by the taper shape of the finline. The resonances in the structure of the finline transition were the strongest enemies who deteriorate the performance of the transition. And we alleviated the resonances using semicircle shaped patch. The designed antipodal finline transition showed good performance as it showed less than -24.2dB of return loss and -0.24dB of insertion loss in the band(57-65GHz) which we suppose to use.

Design of Millimeter-wave Rectangular Waveguide to HMSIW Transition Based on Trapezoidal-shaped Probe

In this letter, a compact rectangular waveguide-to-half mode substrate integrated waveguide (HMSIW) transition is presented. It uses a trapezoidal-shaped probe to couple the energy from rectangular waveguide to HMSIW. A back-to-back test module at Ka-band is fabricated and measured. It provides a return loss better than 15 dB and an insertion loss of 0.85 to 1.3 dB within a frequency range from 25 to 40 GHz. The circuit size of the proposed transition is reduced by approximately 81.8% as compared with the waveguide-to-HMSIW transition using antipodal fin-line. Additionally, no intermediate transition is needed for this transition, which simplify the design of transition circuit. The measurement results agree well with simulation results, which validate the feasibility of the transition. Also, a tolerance analysis is performed via the simulation to verify the reliability of this transition design.

Compact rectangular waveguide to HMSIW transition

A compact waveguide-to-half mode substrate integrated waveguide (HMSIW) transition using antisymmetric tapered probes is proposed. A good matching of field and impendence is achieved by the tapered probes. To verify the proposed transition, a back-to-back test module at Ka-band is fabricated and measured. It provides a return loss better than 14 dB and an insertion loss of 0.35 to 1 dB within a frequency range from 25 to 40 GHz. There is no need of intermediate transition for this design. The size of the proposed transition is reduced by approximately 83.8% as compared with the waveguide-to-HMSIW transition using antipodal fin-line.

A Novel Wideband Transition between Waveguide and SIW

Based on a linearly tapered antipodal finline, a novel low-loss wideband transition between waveguide and substrate integrated waveguide (SIW) is discussed. Results show that a low insertion loss (1.2-2.1dB) and a return loss better than 15dB across the entire Ka-band are obtained for a back-to-back transition structure.

Ultrabroadband power amplifier using 16-way spatial combining finline array

An ultrabroadband power amplifier using 16-way spatial power divider/combiner that using a quasi-TEM-guided wave structure is designed. An oversized coaxial waveguide was used as the host of the dividing/combining circuits that incorporates an antipodal finline array. Galerkin's technique in the spectral domain was used to analyze the antipodal finline. The oversized TEM-guided wave structure and antipodal transitions were designed using the theory of small reflection and near optimum design. A high power amplifier using 16 monolithic-microwave integrated-circuit power amplifiers is built. The measured results show 160% bandwidth impedance match covering the entire 2–18 GHz with maximum output power of 39 dBm CW (Continous Wave) and corresponding gain greater than 11 dB. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:454–460, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27321

Edge-Based Finite Element Method Analysis of the Transmission Characteristics in Antipodal Finline

The transmission characteristics in antipodal finline are analyzed by edge-based finite element method. The cutoff wavelength of the dominant mode and single-mode bandwidth can be changed by adjusting the thickness of metallic fins and dielectric constant of dielectric substrate. Field patterns of the dominant mode and the first higher-order mode for different dimensions and the dielectric constant of dielectric substrate are also illustrated. Numerical results in this paper are considered useful in practical applications.

18–40 GHz low conversion loss double-balanced star mixer using bilateral finline and antipodal finline

A unique broadband millimetre-wave low conversion loss double-balanced mixer based on a star configuration has been designed and demonstrated. The ridged waveguide to bilateral finline transition and the ridged waveguide to antipodal finline transition are used as the local oscillator (LO) and radio frequency (RF) port of the mixer, respectively. The intermediate frequency (IF) signal is orthogonally extracted from the common star-configuration point. The height of the ridge of the double-ridged waveguide is reduced gradually to improve the impedance match and ensure enough space to mount the diodes. The leakage RF signal launched by the antipodal finline is terminated by six plated-through holes through the slot line conductors. A short-circuit formed by the bifurcation of the balanced microstrip line is used to terminate the leakage LO signal launched by the bilateral finline. The measured results show the mixer has low conversion loss (from 3.8 to 7.0 dB), high isolation between all ports (>26 dB), as well as low return loss of the RF port over the frequency range of 18 to 40 GHz. Compared with previously published mixers, this work demonstrates the best performances of the most important parameters of 18–40 GHz mixers.

A 34 to 36 GHz Vector Modulator for Reflected Power Canceller Techniques in LFMCW Radar

In this paper, a 34 to 36 GHz vector modulator for using in low cost and high performance RPC (Reflected Power Canceller) is presented. The key circuit consists of two push-pull (bi-phase) attenuators arranged in phase quadrature and a 3dB quadrature coupler (branch line couplers but not Lange couplers which is different from traditional circuits in Ka band) and a Wilkinson combiner, and then transition from micro-strip to waveguide using antipodal finline. To fully exploit this circuit’s capacity to generate accurate constellations at millimeter-wave frequencies, a generalized theoretical analysis of the (push-pull) vector modulator is presented. Based on the theoretical model and the measured results, the I-Q (push-pull) vector modulator promises to be a vital component for the realization of reflected power canceller in LFMCW (Linear Frequency Modulated Continuous Wave) radar.

Broadband transition between half mode substrate integrated waveguide and rectangular waveguide

A broadband transition between a half mode substrate integrated waveguide and a rectangular waveguide with an antipodal fin-line in its quasi-TEM mode is presented. Experimental results show about 1.3 dB insertion loss and below −15 dB return loss for a back-to-back double transition over 10 GHz bandwidth from 26.5 to 40 GHz (the single transition insertion loss is about 0.65 dB). The transition may be used in low-loss and low-noise front-end circuits of the microwave and millimetre-wave bands.

Broadband substrate integrated waveguide to rectangular waveguide transition with fin-line

A novel broadband transition from a substrate integrated waveguide to a rectangle waveguide with an antipodal fin-line in its quasi-TE mode is presented. Impedance match and field mode gradual changing of transition circuits have been carefully analysed and performed. Experimental results show about a 1.6 dB insertion loss and greater than 12 dB return loss for back-to-back transitions over 10 GHz bandwidth from 26.5 to 40 GHz, so single transition insertion loss is about 0.8 dB. The transition is proposed for low-loss front-end circuits in the millimetre-wave band.

Waveguide-to-planar circuit transition for millimetre-wave detectors

We present a novel design of a waveguide to microstrip or coplanar waveguide transition using a unilateral finline taper. The transition from the unilateral finline mode to the TEM microstrip mode is done directly, avoiding the antipodal finline tapers that have commonly been employed. This results in significant simplification of the design and fabrication, and shortening of the chip length, thereby reducing insertion loss. In this paper we shall present designs at 90 GHz that can be employed in superconducting tunnel junction mixers or Transition Edge Sensor bolometers, and scale-model measurements at 15 GHz.

A 700-GHz SIS Antipodal Finline Mixer Fed by a Pickett–Potter Horn-Reflector Antenna

We report the successful operation of a superconductor-insulator-superconductor (SIS) finline mixer operating near the superconducting energy gap of Nb. The mixer employs a new type of Pickett-Potter horn-reflector (PPHR) antenna, which exhibits low sidelobes and low cross-polarization levels, and yet is easy to fabricate. The SIS tunnel junction and all of the integrated superconducting tuning circuits are fabricated from Nb using planar-circuit technology. The mixer employs an antipodal finline section, deposited on one side of a quartz substrate, which transforms the high impedance of the waveguide (/spl ap/300 /spl Omega/) to the low impedance of the microstrip line (/spl ap/20 /spl Omega/). The Nb/Al-oxide/Nb tunnel junction is fabricated at the same time as the finline circuit. In this paper, we describe the design and testing of the mixer, and pay particular attention to the electromagnetic design of the PPHR antenna. We investigate the noise temperature and gain of the mixer over 642-714 GHz, and analyze the experimental results using rigorous theories that were developed specifically for the purpose. Our investigation demonstrates that finline mixers have good performance both below and above the superconducting energy gap.

V-band high-efficiency broadband power combiner and power-combining module using double antipodal finline transitions

A V-band high-efficiency power-combining module was developed using double antipodal finline structures. The combiner performs the dual functionality of power combining and mode transition from microstrip to waveguide. The measurement of the back-to-back connected combiner demonstrated an insertion loss of 1.2 dB and return loss better than 15 dB around 60 GHz with a 3 dB bandwidth of 18 GHz. The power-combining module incorporating two MMIC power amplifiers demonstrated a combining efficiency higher than 80%.

A 350-GHz SIS antipodal finline mixer

In this paper, we describe the design and operation of a 350-GHz finline superconductor-insulator-superconductor mixer. The mixer is fed by a horn-reflector antenna, and the superconducting circuit is fabricated using planar-circuit technology and fully integrated tuning. An important feature of the mixer is that it employs an antipodal finline section, deposited on one side of a quartz substrate, which transforms the high impedance of the waveguide (/spl ap/300 /spl Omega/) to the low impedance of the microstrip (/spl ap/20 /spl Omega/). The Nb/Al-oxide/Nb tunnel junction is fabricated at the same time as the finline circuit. In this paper, we describe the design procedure in some detail. We pay particular attention to the synthesis of the finline taper and the electromagnetic design of the horn-reflector antenna. We have tested a finline mixer over the frequency range of 330-370 GHz and measured a receiver noise temperature of 90 K, which remained unchanged over the whole frequency range. Our investigation has demonstrated that it is possible to make superconducting finline mixers for frequencies as high as 350 GHz.