The concept of the corrugated via-wall substrate-integrated waveguide (CV-WSIW) reported by the same authors earlier has now been extended to the mm-wave frequency range, and the transitions for this category of SIWs from microstrip line (ML) are presented in this work. A new design of enhanced CV-WSIW for 18-40 GHz frequency range is proposed. The design includes a tapered section of the microstrip line and two rows of metallic vias with the gap between them. They are providing a better impedance match and reduced overall loss. The proposed design offers improved performance in terms of broadband, return loss (RL), insertion loss (IL), and total loss (TL). The laboratory prototypes are developed, and the obtained simulation results show a close agreement with the measured results. The experimental results show the minimum RL of 22dB, IL of 0.22-0.42dB, a fractional bandwidth of 75.80%, a figure-of-merit of 967.9, and the TL below 20% for ML/CV-WSIW transition within 18-40GHz range. Three additional ML/CV-WSIW transitions were also designed and tested, so that four tested transitions cover 8-60GHz range; an additional fifth transition was simulated only in 60-140GHz range.

This work proposes a broadband transition from tapered microstrip line-to-substrate-integrated waveguide (SIW) using parallel half-mode SIW (HMSIW) for C/X-band applications. The proposed transition comprises four sections: a microstrip feed, tapered microstrip line, tapered parallel HMSIWs, and a waveguide section (SIW). Placing the parallel HMSIWs section between the tapered microstrip line section and the SIW part improves the S-parameters characteristics of the near-cut-off frequency. The HMSIWs section has a lower cut-off frequency than the SIW part, about 4.6 GHz. The lower cut-off- frequency is obtained by gradually altering the electromagnetic field mode to reduce reflection. Which helps convert from TEM mode to TM conversion. The proposed transition is designed, simulated, fabricated, and experimentally verified in order to compare between simulated and experimental results. For the back-to-back laboratory prototype of the transition, the experimental return loss results are less than 20 dB in the 4.6 to 11 GHz frequency range. At the same time, the measured minimum insertion loss is lower than 0.37 dB (maximum: 1.51 dB).

This article presents a novel broadband transition from coaxial line to substrate-integrated waveguide (SIW). The SIW wall includes three rows of metallic vias, where the vias of smaller diameter are squeezed between vias of larger diameter. This modification results in a corrugated via-wall SIW (CVWSIW) providing lower loss. Three versions of stubs (rectangular, semicircular, and triangular) are designed around the coaxial line launch on the top metal plane of the SIW. All transition versions are fabricated and tested, and the measurement results are in a good agreement with simulations. The measured more than 14-dB return loss (RL) and fractional bandwidth (FBW) of 75%, 79.4%, and 44.6% (10-dB FBW: 97.14%, 90.5%, and 78.26%) in these versions for the 9-26-GHz frequency range were obtained, respectively. The insertion loss (IL) is less than 0.63, 0.91, and 0.68 dB; the total loss is below 20%, 30%, and 25% for these versions for the same frequency band, respectively.

In this paper, a circularly polarized (CP) substrate-integrated waveguide (SIW)-based H-plane horn antenna with broader impedance bandwidth and higher peak realized gain (PRG) for armature satellite services (X-band, 8-12 GHz) and broadcast satellite (Ku-band, 12-18 GHz) applications is presented. A tapered microstrip transition is used in the feeding section to obtain the broadband characteristics. In addition, the feeding component of the antenna utilizes three quarter-wave transformers to enhance impedance matching and widen the bandwidth. To generate the CP, two rows of rectangular slots are etched from both the top and bottom metal surfaces of the design. The antenna is designed, fabricated, and tested. The measured fractional impedance bandwidth of 41.6%, the 3-dB axial ratio bandwidth of 3.8 GHz, the maximum PRG of 6.95 dBic, the maximum radiation efficiency (simulated) of 87%, and the cross-polarization level below -40 dB have been achieved at the center frequency of 13.2 GHz.

In this paper, a substrate-integrated waveguide (SIW)-based H-plane horn antenna with a broader impedance bandwidth and high peak realized gain (PRG) for broadcast satellite (Ku/K band, 12.5-26.5 GHz) and fixed satellite (K band, 18-26.5 GHz) services applications is presented. A tapered microstrip transition is used in the feeding section to obtain the broadband characteristics. In addition, the multistrip transition also helped to enhance the fractional impedance bandwidth (FIBW), radiation characteristics and to improve the PRG. This mechanism of bandwidth increase can be explained by applying the coupled resonators theory. The antenna is designed, fabricated, and tested. The measured FIBW of 16.3%, the PRG of 10.56 dBi at the end-fire direction, the maximum radiation efficiency of 88.56%, and the cross-polarization level below - 35 dB have been achieved at the center frequency of 19 GHz.

This paper proposes a non-iterative method for the design of Radio Frequency Energy Harvesters (RFEHs) with maximum power conversion efficiency (PCE) at any given input power level. Because of the non-linear interdependency of the rectifier’s input impedance and its input voltage to matching network’s and rectifier’s parameters, the design of an RFEH with maximum efficiency requires numerous lengthy transient simulations of the entire energy harvester. Splitting the design space into two separate spaces which only interact with each other through the input voltage of the rectifier, the design goal can now be redefined to finding an optimum input voltage amplitude that maximizes the efficiency of the rectifier while enabling maximum power transfer from antenna to the input of the rectifier at the same time. Using the proposed method, the number of the required simulations to find optimum design values is significantly reduced compared to all previous methods reported in the literature, which also has been experimentally verified by designing three battery-loaded RFEHs at different input power levels in TSMC’s 130nm CMOS process. To further accelerate the design process, closed-form equations to calculate the efficiency and the input resistance of the rectifier are derived for the battery-loaded Dickson charge pump rectifiers.

This article presents an area and power-efficient psuedo distributed amplifier (Psuedo-DA) beamforming architecture capable of supporting two simultaneous beams. The proposed receiving beamformer is constructed by removing the input transmission line of a distributed amplifier (DA) to directly connect the gain cells to the antenna elements of a phased array and utilizing tunable artificial transmission line (Tunable-ATL) cells of DA’s output transmission line for creating the required progressive phase shifts. Using both ends of the output transmission line, two simultaneous beams can be obtained. The first beam can be steered independently while the other one is formed as an image of the first one. In this article, the theory of operation and the design methodology of the proposed beamformer are presented. In addition, to verify the efficacy of the proposed solution a $K$ -band four-element prototype is fabricated in a standard 65-nm () technology, and the measurement results are reported. The fabricated beamformer provides 110 $^\circ$ beam steering over a 21–23 GHz frequency range. The measured gain, noise figure, and 1 dB compression point (P1dB) are 18 dB, 5.1 dB, and $-$ 18.5 dBm, respectively, with 90-mW dc power consumption and a chip area of 2.05 $\text{mm}^2$ .

This paper presents a Tapered Tunable Transmission Line (Tapered TTL) phase shifter that achieves a higher area efficiency than conventional Tunable Transmission Line (TTL) phase shifters while maintaining the same phase shift range with similar insertion losses. A systematic methodology is provided for the optimum design of the proposed phase shifter to maximize its area efficiency while providing the desired phase shift range and satisfying the maximum allowed input/output return and insertion losses. To verify the efficacy of the proposed solution, an eleven-cell phase shifter is fabricated in a standard 65-nm Complementary Metal–Oxide–Semiconductor (CMOS) technology and the measurement results are reported. The fabricated circuit provides a 180-degree phase shift over the frequency range of 16.5 to 31 GHz with an average insertion loss of 7.2 dB. The proposed design presents a 25 percent reduction in the chip area per unit delay in comparison to the conventional design with the same average insertion loss.

This paper proposes the Corrugated Via-Wall Substrate Integrated Waveguide (CVWSIW) (with enhanced performance compared to the traditional SIW) and the transitions to this newly proposed CVWSIW from a conductor-backed coplanar waveguide (CB-CPW). The CB-CPW slot lines and the gap between two metallic via rows play a prominent role in widening the bandwidth and reducing the loss. The CB-CPW-CVWSIW transition is initially designed in the 4–8 GHz (C-band) range. Following the same design procedure, the transitions are made for other five different bands to cover the frequencies from 2 to 40 GHz. Improved performance in terms of bandwidth, insertion loss, and total loss is the benefit of the designed transitions with the proposed CVWSIW. Laboratory prototypes of the transitions are fabricated and experimentally measured to cross verify the simulation results. The measured results show, for example, the minimum return loss of 15 dB, maximum insertion loss of 0.36 dB, and fractional bandwidth of 62.16% for C-band.

In this paper, a substrate integrated waveguide (SIW)-based H-plane horn antenna with enhanced gain made on a very thin substrate (0.009λ0) is proposed for X-band application. Improved impedance matching is obtained by implementing three stepped quarter-wave transformers in the feed section and four circular slots at the front of the horn. Two rows of teflon vias are used to enhance the gain, and the corrugated wall technique is also implemented to improve other antenna radiation characteristics. The measured fractional impedance bandwidth of 5.22%, the gain of 10.82 dBi, the radiation efficiency of 88.56%, the front-to-back ratio of ≈15 dB, and the low cross-polarization level have been achieved at 10.71 GHz.

This paper presents a substrate integrated waveguide (SIW) cavity slot antenna for the dedicated short-range communication (DSRC) band. The DSRC band (5.9GHz) covers the vehicle-to-vehicle communication frequency range. Conductor-backed coplanar waveguide is used to feed the antenna. To ensure the improvement in the bandwidth, the out-of-band harmonics are suppressed by employing two quarter wave resonators and a shorting pin in the feed of the antenna. The antenna radiation characteristics are also improved by good impedance matching that is achieved by placing two between the radiating patches. The SIW concept implemented in the antenna is reducing the cross-polarization level and lateral leakage. The antenna is designed, fabricated, and measured to validate the design approach. The antenna achieves fractional bandwidth of 8.8%, with the gain of 7.45dBi. Furthermore, the measurement also indicated the radiation efficiency of 88.68% and cross-polarization level below -33dB.

This paper is presenting a broadband, low-profile ( $0.008 \lambda_{0}$ ) substrate-integrated waveguide (SIW) H-plane horn antenna with the reduced side lobes and improved front-to-back ratio (FTBR). This is achieved implementing three rectangular slots near the coaxial feed. The hexagonal slots in front of the horn aperture are used to improve impedance matching. The measured fractional impedance bandwidth of 29.5% (3.25 GHz), the maximum gain of 5.52 dBi (minimum: 2.85 dBi), the maximum radiation efficiency of 95.99 %, the FTBR of 15.83 dB, and the low cross-polarization level have been achieved at the frequency of 9.85 GHz.

This paper presents the design of a differential dual-band three-layer substrate integrated waveguide (SIW) cavity-backed antenna. The SIW has three cross-shaped slots and two shorting pins to facilitate radiation and improve impedance matching. The measured fractional bandwidth of 1.2 and 2.06%, peak gain of 5.67 and 6.99 dBi, radiation efficiency of 79.75 and 92.78%, and cross polarization level more than 37.94 dB have been achieved at resonating frequencies of 10.66 and 11.64 GHz, respectively. The proposed antenna is suitable for X-band application by comparing its output parameters with the previously reported results

The paper considers the transition from conductor backed coplanar waveguide (CB-CPW) to substrate integrated slab waveguide (SISW). The SISW concept is described, it improves the single-mode impedance bandwidth, reduces insertion loss, and the overall loss of the transition. Design example is presented for 12-18 GHz frequency range. The parameters of the transition laboratory prototype are measured to validate the claims.

This brief describes a transition from conductor-backed-coplanar waveguide (CB-CPW) with substrate-integrated coaxial line (SICL) to substrate integrated waveguide (SIW). The transition is designed for the C-band frequency range. The CB-CPW slot lines play the main role in widening the bandwidth. These CPW slot lines are providing excitation of both even and odd mode waves in SIW, which improves the impedance bandwidth. Using the proposed concept, the measured single-mode fractional impedance bandwidth of 63.34%, the minimum insertion loss of 0.16 dB, and the overall loss below 25% are achieved. The simulated results are found to be in good agreement with the experimental ones obtained for the prototype developed in the laboratory.

The letter demonstrates a coaxial transmission line-to-substrate integrated waveguide (CT-SIW) transition using aperture-coupling approach. The method broadens the bandwidth (BW) and reduces the transition insertion loss (IL). Two coaxial line supports with apertures for coupling are attached at the ends of substrate integrated waveguide (SIW). The copper inlaid of the apertures increases coupling of the coaxial line to SIW and can be controlled by the aperture length and the length of the line wire put in the aperture. The transition was designed, fabricated, and experimentally evaluated. The transition provides the measured 10 dB return loss (RL) fractional BW (FBW) of 104.3%, and 15 dB RL (FBW) of 78.06%. The IL of 0.37 to 0.87 dB at 19.63–62.7 GHz frequency range was obtained. The measured results are well correlated with the simulated ones.

This paper presents the design of a low-profile dual-band substrate integrated waveguide (SIW) based H-plane horn antenna with microstrip feeding. The dual band is generated by implementing four different types (levels) of vias in the flare part of the horn. The feeding section of the antenna employs three quarter-wave transformers to improve the impedance matching and bandwidth. The measured fractional bandwidths (FBWs) of 3.08 and 1.23%, the peak gains of 6.22 and 6.02 dBi, the radiation efficiencies of 89.55 and 85.24%, and cross-polarization levels more than 47.29 and 33.43 dB have been achieved at resonating frequencies of 13.63 and 14.61 GHz, respectively. The proposed antenna is designed for Ku-band applications.

The paper considers a new class of polynomial filters which is an extension of the Bessel (Thomson) filters. This extension is achieved considering the difference of two weighted Bessel polynomials. The weight of the subtracted polynomial is including the multiplier an the choice of which defines the class of resulting filters. When an = 0 one obtains the transfer functions of regular Bessel (Thomson) filters. When an =1 one obtains the Stokes filters. The Stokes filters are faster than Bessel filters but have larger step response overshoot. Using the range of −1 < an ≤ 2 one obtains the stable filters with controllable step transient response overshoots. The upper border for an is defined by the stability condition of higher order filters, the low border is defined by the non-monotonicity conditions.

The paper considers the design and tuning of oscillators using active inductors with ungrounded capacitor. The oscillator using this type of active inductor allows one to achieve high oscillation frequencies with low power consumption. Tuning of this oscillator using the variation of bias current or transistor sizes may result in moderate and even weak inversion of the transistors constituting the active inductor. In approaching the operation close to the threshold voltage, the transistor transconductance and the gate-source capacitor are reduced. The paper gives the design examples considering these particularities which are usually neglected and provides the recommendations on the limits of tuning currents and transistor geometry variations.

This paper presents a wide-tuning range dual-mode millimeter wave (mm-wave) voltage controlled oscillator (VCO) incorporating high quality-factor (Q) transformer-based variable inductors. A high Q switched inductor with two different values is proposed by constructing the load of a transformer of a high Q fixed capacitor in series with a lossless switch structure that does not add any loss to the LC-tank as implemented by changing the signals mode across the capacitor. By choosing a proper center frequency for each mode and sufficient frequency overlap, a wide frequency tuning range (FTR) mm-wave VCO can be designed. It provides almost twice higher tuning range while keeping phase noise (PN) nearly the same as the two-mode VCO designed with two standalone inductors. Fabricated in a 65 nm CMOS process, the VCO demonstrates the measured FTR of 22.8% from 64.88 to 81.6 GHz range. The measured peak PN at 10 MHz offset is -114.63 dBc/Hz and the maximum and minimum corresponding figures of merit FOM and FOMT are -173.9 to -181.84 dB and -181.07 to -189 dB, respectively. The VCO cores consume 10.2 mA current from 1 V power supply, and the occupied area is 0.146 ×0.205 mm 2 .