Showing papers on "Return loss published in 2021"

Miniaturised tri-band microstrip patch antenna design for radio and millimetre waves of 5G devices

Abstract: This research presents an extremely small, cheap and simple structure of multiple bands antenna, where is the proposed design comprise square-slotted a microstrip patch antenna with triple bands of RF and mm-wave for 5G. The conducting material is a perfect electrical conductor on both sides. The antenna is printed on FR-4 lossy with a 3.9 of epsilon. Our tiny antenna has a size of 1.5357 x 1.5357 mm 2 . First, the design parameters were calculated using formulas and then these were simulated by the CST MWS. The simulation results show the antenna performance at the RF band from 0 to 3.4096 GHz with 3.29 gain, a value of return loss S 11 and bandwidth of -13.229644 and 3.4096 GHz. The designed antenna works at the mm-wave band ranges 43.5-64 GHz with 3.49 gain, -42.419084 S 11 and 20.252 GHz BW. Our antenna can also operate at the mm-wave from 81-95 GHz with -22.269547 S 11 , 4.52 gain, and 14.085 GHz BW. The small size and supported bandwidth of the designed antenna is suitable for thin and fast transmission devices.

A 200-225-GHz Manifold-Coupled Multiplexer Utilizing Metal Waveguides

Abstract: This article presents a 220-GHz four-channel, noncontiguous, and manifold-coupled waveguide multiplexer for future terahertz (THz) multichannel communication application. The multiplexer is composed of four Chebyshev bandpass filters based on metal waveguide technology. Through a unique design in which the tuning dimensional variables are reduced to 14 and a co-design of low-order electromagnetic (EM) distributed models and full-wave EM models, the design optimization is achieved with a good computational efficiency and design accuracy. The proposed multiplexer is fabricated by high-precision computer numerical control (CNC) milling technology, in which the fabrication errors are evaluated to be within ±3 μm. The measured results exhibit 1.7 dB of in-band insertion loss and better than 15 dB of average common-port return loss for each of the channel filter. The measured results are all in good agreement with the simulated ones, thereby validating the complete design procedure.

Design and implementation of miniaturized wideband microstrip patch antenna for high-speed terahertz applications

Abstract: In the twenty-first century, graphene is widely used in wireless communication, especially in terahertz applications because of its amazing electrical, mechanical, and optical properties. This paper presents a graphene-based microstrip patch antenna at 0.72 THz resonant frequency for wireless communication. The proposed antenna shows 37.50% impedance bandwidth ranging from 0.53 to 0.84 THz at the center frequency of 0.72 THz. The result is demonstrated in terms of return loss (s11 < − 10 dB), voltage standing wave ratio (VSWR), input impedance, E-plane, and H-plane radiation pattern. The designing and simulation are performed using a full-wave electromagnetic simulator CST microwave studio based on the finite difference time domain method. The simulation output shows a minimal return loss − 59.97 dB, VSWR 1.007, and good radiation pattern at 0.72 THz resonant frequency, which would be an excellent candidate for future wireless communication as well as medical imaging, homeland defense system, explosive detection, and material characterization application.

10 Element Sub-6-GHz Multi-Band Double-T Based MIMO Antenna System for 5G Smartphones

Abstract: A 10 element multiple input multi output (MIMO)/Diversity antenna system is considered to work in Sub-6 GHz frequency range. The proposed design can work in long term evolution (LTE) band 42(3.4-3.6 GHz), LTE band 43(3.6-3.8 GHz) and LTE band 46(5.15-5.925 GHz). The proposed design consists of 10 identical and highly isolated T-shaped slot antennas fed with T-shaped lines. All three bands have the return loss values ( 83%) in free space. The peak value of envelope correlation coefficient is 0.06 and the calculated value of ergodic channel capacity is found to be greater than 41bps/Hz in all the bands.The effect of hand grip as well as the presence of battery and LCD screen is investigated. Simulated results are validated via fabrication and measurement of the proposed design.

Design and simulation of fixed–fixed flexure type RF MEMS switch for reconfigurable antenna

Abstract: This Paper Presents the design and simulation of RF MEMS switch taken on Microstrip patch antenna loaded with the circular type CSRR. The Tunability of the patch antenna is achieved when the two switches moves from upstate to down state arranged on the feeding line provided with the CPW. The actuation voltage required to move the switch downwards is 7.6 V. The switch operates at transition time of 0.8 µsec with the capacitance ratio 10. The return loss (S11) of antenna − 28.67 dB is observed at the frequency of 19 GHz when one switch is in on state and at 16 GHz frequency the S11 of − 29.31 dB is achieved by actuating the 2 switches at a time, which gives the reconfigurable property of the antenna. The antenna provides 2 GHz and 5 GHz frequency shift when single and both the switches are in on state. The antenna can be tuned for various applications in the range of 15–30 GHz frequency. The characteristics of switch has been observed by simulating the switch design in FEM tool and results have been compared with theoretical calculations. The tunable characteristics of antenna has been observed and presented by using HFSSV.13 tool.

Design and Synthesis of Multi-Mode Bandpass Filter for Wireless Applications

Abstract: In this paper, a compact bandpass filter with improved band stop and band pass characteristics for wireless applications is built with four internal conductive poles in a single resonating cavity, which adds novel quad-resonating modes to the realization of band pass filter. This paper covers the design and testing of the S-band combline coaxial cavity filter which is beneficial in efficient filtering functions in wireless communication system design. The metallic cavity high Q coaxial resonators have the advantages of narrowband, low loss, better selectivity and high potential for power handling, as compared to microstrip filter in the application to determine the quality factor of motor oils. Furthermore, the tuning of coupling screws in the combline filter allows in frequency and bandwidth adjustments. An impedance bandwidth of 500 MHz (fractional bandwidth of 12.8%) has been achieved with an insertion loss of less than 2.5 dB and return loss of 18 dB at the resonant frequency. Four-pole resonating cavity filters have been developed with the center frequency of 4.5 GHz. Insert loss at 0 dB and estimated bandwidth at 850 MHz and a quality factor of 4.3 for the band pass frequencies between 4 and 8 GHz is seen in the simulated result.

A Wideband Dual-Polarized Antenna for Millimeter-Wave Applications

Abstract: A wideband dual-polarized magneto-electric (ME) dipole for millimeter waveband applications is presented. The ME dipole consists of four shorted patches, which are fed by two pairs of T-shaped probes orthogonally oriented on the same layer. The feed lines are connected with the T-shaped probes through metallic vias. Simulated overlapped impedance bandwidth of 50% with return loss larger than 10 dB, gain up to 9.4 dBi, and isolation higher than 17.8 dB between dual polarizations are achieved. By combining the antenna elements with single-layered feed networks, a $2 \times 2$ array is designed, fabricated, and measured. The overlapped working bandwidth is 50%, with gain up 14.8 dBi. With the advantages of wide bandwidth, single-layered radiation structure, and promising radiation pattern, the proposed antenna with dual polarizations would be attractive for millimeter-wave antenna in package (AiP) applications.

Performance improvement of H-Shaped antenna with Zener diode for textile applications

Abstract: Wireless network becoming an integral part of daily existence, and it is expected to become much more so in the future. The dual-band frequency-reconfigurable H-shaped microstrip antenna fed by two...

Wideband and high-gain patch antenna with reflective focusing metasurface

Abstract: In this paper, a high-gain and wideband circular polarization (CP) patch antenna using reflective focusing metasurface was proposed and demonstrated. The initial design of patch antenna is made of a slot planar patch radiation part fed by coplanar waveguide (CPW). The simulated return loss below −10 dB of the initial design is from 6.2 to 13.8 GHz with the relative bandwidth of 76%, and the average gain is only about 4.5 dBi. In addition, the simulated 3-dB axial ratio bandwidth (ARBW) of the initial design is 78.7% from 6 to 13.8 GHz. The antenna structure was modified to enhance the gain and radiation performance by adding the reflective focusing geometric metasurface. The metasurface with wideband high efficiency cross-polarization reflection, is arranged to construct the phase gradient paraboloid for energy gathering. Simulation results indicated that the antenna combined with reflective focusing metasurface achieves an effective wideband impedance bandwidth (return loss

High-Gain Compact Circularly Polarized X-Band Superstrate Antenna for CubeSat Applications

Abstract: In this letter, a concept of a high-gain circularly polarized X-band antenna employing a partially reflecting surface (PRS) has been presented. In the initial antenna analysis, the influence of parasitic element size in the PRS structure on antenna radiation pattern parameters has been investigated and the optimal arrangement of the elements has been identified. The proposed antenna provides a wide bandwidth of return loss above 10 dB of 20% (8–9.8 GHz) and circular polarization (CP) in a frequency range 8.35–8.95 GHz. The final design is compact (62 × 62 × 22.2 mm) and lightweight (29.7 g), which makes it suitable for use not only in CubeSat X-band communication systems but also in drones and high-altitude pseudosatellite applications.

Efficient SIW-Feed Network Suppressing Mutual Coupling of Slot Antenna Array

Abstract: In this communication, an effective method to suppress mutual coupling between two substrate-integrated waveguide (SIW) slot antenna arrays is presented. To achieve that, a decoupling feed network is used. The feed network is composed of a two-layer directional coupler that is connected to two SIW-slot antenna arrays directly to establish an indirect coupling with controlled magnitude and phase, which can effectively reduce the direct coupling generated by surface waves between the array elements. A $2 \times 4$ array of slot antenna as well as the proposed decoupling network is designed, fabricated, and measured to illustrate the effectiveness of the proposed technique. The measured and simulated results verified the good decoupling performance. The measured mutual coupling is about −35 dB at the center frequency without negatively affecting the return loss and radiation patterns. The proposed mechanism of the decoupling network is simple and successfully used in SIW slot antenna arrays.

CPW-Fed Flexible Ultra-Wideband Antenna for IoT Applications.

Abstract: In this article, an inkjet-printed circular-shaped monopole ultra-wideband (UWB) antenna with an inside-cut feed structure was implemented on a flexible polyethylene terephthalate (PET) substrate. The coplanar waveguide (CPW)-fed antenna was designed using ANSYS high-frequency structural simulator (HFSS), which operates at 3.04–10.70 GHz and 15.18–18 GHz (upper Ku band) with a return loss < −10 dB and a VSWR < 2. The antenna, with the dimensions of 47 mm × 25 mm × 0.135 mm, exhibited omnidirectional radiation characteristics over the entire impedance bandwidth, with an average peak gain of 3.94 dBi. The simulated antenna structure was in good agreement with the experiment’s measured results under flat and bending conditions, making it conducive for flexible and wearable Internet of things (IoT) applications.

A Compact 28/38 GHz MIMO Circularly Polarized Antenna for 5 G Applications

Abstract: A novel design is introduced for dual-band operation at 28/38 GHz for improving microstrip antennas. Also, the design support circularly polarized antenna that works in millimetre band applications. This proposed antenna is attached to a circular hole in the centre of the patch with four slits embedded in the corners. Also, small holes are etched at sides of the patch to achieve the resonant frequencies and improve the return loss value with achieving very wide band at 38 GHz. A single-feed circularly polarized antenna at 28 GHz and 38 GHz with return loss − 30 dB and − 42 dB, respectively, which makes it suitable for operation at 5 G wireless communication designs. A single element design can cover the frequency ranges of 27.6–28.3 GHz at 28 GHz with bandwidth 2.5% and 35.2–47.2 GHz at 38 GHz with very wide bandwidth 32.4%. Simulated results show that the proposed antenna has good circular polarization in both frequencies of left-hand circular polarization (LHCP). On the other hand, MIMO antenna with four ports is constructed. The four ports are arranged at the corner and middle of substrate with dimension 100 × 75 × 0.508 mm3. Meanwhile, resonant implementation frequencies in a millimetre wave of the MIMO achieved more mutual coupling minimization that effectively accomplished <− 36 dB. In addition, the numerical and experimental results are achieved to evaluate the performance of both single- and four-port MIMO antennas. The diversity gain (DG), envelop correlation coefficient (ECC), total active radiation coefficient (TARC) and channel capacity loss (CCL) also are calculated, and the results are suitable for 5 G applications.

Design and Experimental Analysis of Multiband Compound Reconfigurable 5G Antenna for Sub-6 GHz Wireless Applications

Abstract: In this paper, a printed low-profile antenna with frequency and pattern reconfigurable functionality is designed in three modes. Each mode operates at different frequency bands and has several options available for pattern reconfiguration in these bands. The proposed antenna consists of eight pin-diode switches (S1 to S8). The switches S1 and S2, installed in the radiating patch, are used for frequency reconfigurability to control the operating bands of the antenna. The rest of the six switches (S3, S4, S5, S6, S7, and S8), loaded in the stubs on the rear side of the antenna, are used for pattern reconfiguration to control the main lobe beam steering. When all switches are off, the proposed antenna operates in a wideband mode, covering the 3.82-9.32 GHz frequency range. When S1 is on, the antenna resonates in the 3.5 GHz (3.09-4.17 GHz) band. When both S1 and S2 are on, the resonant band of the antenna is shifted to 2.5 GHz band (2.40-2.81 GHz). A very good impedance matching with a return loss of less than -10 dB is attained in these bands. The beam steering is done at each operating frequency by controlling the on and off states of the six pin-diode switches (S3, S4, S5, S6, S7, and S8). Depending on the state of the switches, the antenna can direct the beam in seven distinct directions at 4.2 GHz, 4.5 GHz, and 5 GHz. The main beam of the radiation pattern is steered in five different directions at 5.5 GHz, 3.5 GHz, and 2.6 GHz operating bands for the given state of the mentioned switches. The proposed antenna supports several sub-6 GHz 5G bands (2.6 GHz, 3.5 GHz, 4.2 GHz, 4.5 GHz, and 5 GHz) and can be used in handheld 5G devices.

PMC Packaged Single-Substrate 4 × 4 Butler Matrix and Double-Ridge Gap Waveguide Horn Antenna Array for Multibeam Applications

Abstract: A perfect magnetic conductor (PMC) packaging concept is utilized at 30 GHz, which suppresses the higher order cavity modes, improves insertion losses, and helps in developing packaged microstrip lines (PMSLs) and double-ridge gap waveguide (DRGW) transmission lines. The Quasi-TEM PMSLs are used to design quadratic hybrid, crossover, and phase shifters as components of a wideband $4\times 4$ Butler matrix (BM) on a single substrate. Two types of electromagnetic bandgap (EBG) unit cells—full height and half height—are investigated to realize artificial magnetic conductors (AMCs) required for the present design. A parametric study is performed for all components. BM is numerically assembled from these components and analyzed. It achieves a 5-GHz (28–33 GHz) bandwidth with return loss and isolation, both better than 15 dB. At 30 GHz, the insertion loss is 0.8 ± 0.3 dB, and antenna-ports’ phase distributions are ±° and ±°. $E$ -plane-flared horn antennas terminate the BM antenna ports as a linear array. The DRGW horn antenna is designed to reduce the scan loss within an array environment. The $H$ -plane fan-beam switching covers ±° with a maximum gain of 11.7 and 11.2 dBi for $1R$ and $2R$ beams, respectively. The $H$ -plane element pattern and the half-height EBG AMC at the array aperture help to maintain 0.5 dB of gain loss for the outer beams ( $2R$ and $2L$ ) compared to the inner beams ( $1R$ and $1L$ ). The multibeam prototype is the right candidate for millimeter-wave 5G base station and can easily be scaled to higher frequency bands.

A Systematic Design of a Compact Wideband Hybrid Directional Coupler Based on Printed RGW Technology

Abstract: Printed ridge gap waveguide (PRGW) is considered among the state of art guiding technologies due to its low signal distortion and low loss at Millimeter Wave (mmWave) spectrum, which motivates the research community to use this guiding structure as a host technology for various passive microwave and mmWave components. One of the most important passive components used in antenna beam-switching networks is the quadrature hybrid directional coupler providing signal power division with 90° phase shift. A featured design of a broadband and compact PRGW hybrid coupler is propose in this paper. A novel design methodology, based on mode analysis, is introduced to design the objective coupler. The proposed design is suitable for mmWave applications with small electrical dimensions ( $1.2\,\,\lambda _{o} \times 1.2\,\,\lambda _{o}$ ), low loss, and wide bandwidth. The proposed hybrid coupler is fabricated on Roger/RT 6002 substrate material of thickness 0.762 mm. The measured results highlight that the coupler can provide a good return loss with a bandwidth of 26.5% at 30 GHz and isolation beyond 15 dB. The measured phase difference between the coupler output ports is equal $90^\circ \pm ~5^\circ $ through the interested operating bandwidth. A clear agreement between the simulated and the measured results over the assigned operating bandwidth has been illustrated.

Design of a Dual Band SNG Metamaterial Based Antenna for LTE 46/WLAN and Ka-Band Applications

Abstract: The non-existing properties of the metamaterial surfaces can be utilized to improve the antenna radiation characteristics. In this article, a design and performance analysis of a Single Negative (SNG) metamaterial based antenna is imparted for LTE 46/WLAN and Ka-band (like in satellite communication for the receiving side) applications. The unit cell of the metamaterial surface exhibits negative permittivity and positive permeability; yielding a high magnitude positive refractive index, is used to improve and analyze the performance of the proposed monopole antenna element. The proposed SNG based antenna covers a −10 dB bandwidth from 5.35-5.69 GHz (LTE 46/WLAN) and 17.81-20.67 GHz (Ka-band). The total size of the proposed antenna element is $20.2\times 28$ .4 mm2 while a $2\times 3$ SNG metamaterial surface is used at the back of the antenna element which improves the gain from 4.52 dB to 9.13 dB for the desired Ka band and 1.17 to 5.04 dB for the LTE 46/WLAN band. Furthermore, for the LTE 46/WLAN frequency band, the impedance matching also gets better, resulting in the return loss improvement from −11 dB to −32.4 dB. Moreover, the radiation efficiency is also improved by more than 10 % for the Ka band after employing the SNG metamaterial surface. The measured results fall in good agreement with the simulated one and make the proposed SNG metamaterial based antenna design competent for the LTE 46/WLAN and Ka-band (like in satellite communication for the receiving side) applications.

Significant Bandwidth Enhancement of Radial-Line Slot Array Antennas Using a Radially Nonuniform TEM Waveguide

Abstract: Radial line slot array (RLSA) antennas have attractive features, such as high gain, high efficiency, and planar low profile, but their gain–bandwidths have been limited to less than 10%. This article presents a method to significantly increase the gain–bandwidth of RLSAs to over 30%. The key to the method is the application of a nonuniform radial TEM waveguide as opposed to the radially uniform TEM waveguide used in conventional RLSAs. Hence, the condition for maximum radiation is satisfied at a wide range of frequencies by different sections of the RLSA. To demonstrate the concept, several circularly polarized RLSA designs and one prototype are presented. The measured results of the prototype demonstrate an unprecedented 3 dB gain–bandwidth of 27.6%, a peak gain of 27.3 dBic, 3 dB axial ratio bandwidth greater than 31.1%, and a 10 dB return loss bandwidth greater than 34.8%. The overall measured bandwidth of the RLSA in which gain variation and axial ratio are within 3 dB and return loss is greater than 10 dB is from 9.7 to 12.8 GHz or 27.6%. Its extremely high measured gain–bandwidth product per unit area (GBP/A) of 88 indicates excellent overall performance in terms of bandwidth, gain, and area.

Compact Square Substrate Integrated Waveguide Filtering Power Divider With Wideband Isolation

Abstract: In this letter, a new compact filtering power divider (FPD) on the square substrate integrated waveguide (SIW) with wideband isolation is proposed. As the isolation network is embedded in a square SIW cavity, good in-band isolation, compact structure, and low insertion loss can be simultaneously attained. The proposed FPD consists of the coplanar waveguide feeding line of Port 1, the capacitor, a resistor, and the square SIW cavity. TE101, TE201, and slot-line modes can realize third-order filtering response. Center frequency ( $f_{0}$ ) and bandwidth of the filtering response can be independently adjusted. In order to achieve out-of-band isolation, Port 2/3 is placed in the specific position to suppress the high-order modes according to the electric-field distributions of these modes. Finally, a prototype with in-band return loss of 20 dB across 5.59–6.4 GHz is designed at 5.99 GHz. The bandwidths of isolation higher than 21 dB and upper stopband attenuation higher than 20 dB are extended to $2.79f_{0}$ and $2.83f_{0}$ , respectively.

The Design of a Wideband Antenna with Notching Characteristics for Small Devices Using a Genetic Algorithm

Abstract: This paper presents the design and realization of a compact printed ultra-wideband (UWB) antenna with notching characteristics for compact devices using a genetic algorithm. The antenna is capable of mitigating an adjacent sub-band ranging from 3.75 to 4.875 GHz, mainly used by many applications and standards such as WiMAX, WLAN and sub-6-GHz. The notch band functionality is achieved by etching out two symmetrical slots from the pentagonal radiating element. The simulation and measured results demonstrate that the proposed antenna overperformed compared with state-of-the-art antennas in terms of compactness with an overall size of 20 mm×15 mm×0.508 mm. Moreover, the proposed design shows a large bandwidth in the UWB region with a fractional bandwidth of 180% with respect to the center frequency of 5.25 GHz. The antenna also presents omnidirectional radiations all over the operation band and a good return loss performance.

A Compact Dual-Band Slot Antenna With Horizontally Polarized Omnidirectional Radiation

Abstract: A dual-band horizontally polarized omnidirectional antenna for WiFi applications is proposed in this letter, which consists of a 3-D radiation slot on a metal box and three folded patches inside. The 3-D slot is formed by connecting two trapezoid slots at top and bottom of the box with a rectangle slot at the vertical side. Then, the radiation slot is excited by a folded patch connected to the feed line and produces two resonances at 2.45 and 5.5 GHz. With the help of two parasitic patches beside the excited patch, the higher frequency band is broadened. Measured results show that the antenna has two 10 dB return loss operating bandwidths of 5.32% and 20.56%. Moreover, the measured out-of-roundness for the horizontal radiation pattern is less than 2.4 dB in lower frequency band and that of higher frequency band is less than 5.3 dB. Besides, the antenna maintains a compact size of only 22 mm × 10 mm × 25 mm (0.18 λ 0 × 0.08 λ 0 × 0.20 λ 0, where λ0 is the wavelength of the lowest operating frequency), with the gain about 2 dBi and the cross-polarization ratio greater than 20 dB in the entire band.

Non-Volatile Multiport DC–30 GHz Monolithically Integrated Phase-Change Transfer Switches

Abstract: This paper reports two configurations of non-volatile multiport transfer switches based on the phase change material (PCM) germanium telluride. The monolithic transfer switches are developed in-house using a custom microfabrication process designed to operate over a wideband dc–30GHz. A C-type switch configuration is presented with two operational states in a highly miniaturized package with the device core area under 0.09mm2. A unique, highly versatile multiport R-type switch configuration is proposed with three operational states that offers improved system flexibility, reducing the number of switches for routing. The R-type switch configuration has a device core periphery under 0.2mm2. The presented devices are compared with the current state-of-the-art switch technologies. The transfer switches exhibit a measured insertion loss of less than 1.5dB, return loss better than 18dB, and +35.5dBm measured power handling capability with switching speed less than 2 $\mu \text{s}$ .

A compact 4 × 4 SIW beamforming network for 5G applications

Abstract: This paper presents a compact SIW beamforming network (BFN) for feeding a four-beam slot array antenna, which can be used in 5G mobile applications. The proposed BFN is realized with a new 4 × 4 multi-aperture coupler (MAC) and a 4 × 4 “equal length unequal width” phase shifter. The antenna operates in the range of 28–32 GHz, and generates four beams with the maximum gain of 11.2 dBi in the directions of ±15° and ±49°. To validate the design procedure and the simulation results, the proposed antenna is fabricated and tested. The measured results show that the return loss for the input ports is more than 10 dB, and the isolations between them are more than 13 dB, across the operating frequency band. The overall occupied area of the antenna structure, including the proposed BFN, is 56.5 mm × 21 mm, which shows 33% size reduction compared to similar designs.

SLM Printed Waveguide Dual-Mode Filters With Reduced Sensitivity to Fabrication Imperfections

Abstract: This letter presents an eighth-order dual-mode waveguide filter, fabricated using the selective laser melting (SLM) technique. The filter employs four dimpled ellipsoid dual-mode resonators, operating at the fundamental TM101 mode. During printing, the filter can be mechanically self-supported without any internal supports. Compared to the filters employing tuning posts, the proposed filter is less sensitive to fabrication errors in terms of their impacts on passband return loss (RL), frequency shift, and bandwidth. The filter was demonstrated at WR-112 band (7–10 GHz), with a measured insertion loss of 0.25–0.4 dB and an RL >15 dB across the passband of 8–8.46 GHz.

Antennas in Glass Interposer For sub-THz Applications

Abstract: The development of next generation (6G) wireless communications is expanding new spectrum bands into sub-terahertz (sub-THz) frequencies above 100 GHz, and the antenna is a key component in RF front-end modules (FEM) for such frequency bands. This paper demonstrates integrated packaging solutions for antenna components in D-band by using glass-based package. With the assistance of full-wave simulation in HFSS software, we design sub-THz patch antennas operating at 140 GHz frequency band, and form arrays of such patch antennas for 5G+/6G (sub-THz) wireless communication applications. The patch antennas and feeding networks are implemented by microstrip structures on the top of the glass interposer, with ground planes beneath. Build-up layers of polymer dry films are laminated on a glass core substrate for multi-layer copper metallization, and copper structures are patterned on the polymer layers. For precise fabrication of the antenna and feeding structures in package, we utilise the semi-additive patterning process to deposit the copper structures. By forming patch antenna arrays, we obtain 10.6 dBi gain using a 4-element linear array and 16.2 dBi gain using a 4-by-4 2-D rectangular array. The feeding methods of patch arrays are also discussed in the paper. The bandwidths achieved for these arrays are 7% (10 GHz) and 5% (7 GHz), respectively, based on return loss measurements. The measurement results present good match to simulation models, considering the uncertainties at such high frequencies. We believe that this is the first demonstration of glass-based antenna-in-package solution in D-band frequencies. Antenna structures on glass substrates illustrated in this paper represent one of the basic building blocks for the heterogeneous integration of sub-THz FEM in glass-based packages.

Ultra-Broadband Bandpass Filter Using Linearly Tapered Coupled-Microstrip Line and Open Loop Defected Ground Structure

Abstract: This brief presents a novel highly compact ultra-broadband bandpass filter (BPF) using linearly tapered coupled-microstrip line (LTC-ML) and open loop defected ground structure (OL-DGS). The filter structure consists of a LTC-ML with open-circuited stubs (OCSs) and an OL-DGS etched on the ground. The linearly tapered and tightly coupled microstrip OCS can function as two resonators, and with an associated enhanced coupling structure to OL-DGS, it leads to a very compact three-pole filter. The proposed filter also exhibits a quasi-elliptic function response, where two transmission zeros (TZ) closer to each side of the passband to improve selectivity and one TZ at higher side of the upper stopband, can be observed. An approximate in-line synthesis of the proposed third-order filter with three TZs has also been performed, which shows similar characteristics like the desired response. The simulated and measured results of the filter are in good agreement with each other, showing a wide 10 dB return loss (RL) bandwidth from 4.5 to 12 GHz, insertion loss better than 1.5 dB and group delay variation of lesser than 0.2 ns in the whole passband. Furthermore, it has a very compact size of $0.31\lambda _{g}\times 0.55\lambda _{g}$ at the central frequency of 8.25 GHz.