A 60‐GHz on‐chip slot‐array antenna in integrated‐passive‐device technology for antenna‐in‐package applications

A new millimeter‐wave antenna structure on a low‐cost, production platform integrated passive device technology is presented. The antenna consists of a 2‐by‐1 array of slot antennas at 60 GHz. An in‐house developed on‐chip antenna measurement setup was used to characterize the fabricated antenna. The measurement results show an antenna gain of more than 5 dBi with a return loss of 18 dB at 60 GHz. The better‐than‐10‐dB impedance bandwidth of the antenna covers the 60‐GHz unlicensed band from 57 to 64 GHz. The 3‐dB beamwidths of the antenna are 105° and 76° at E‐plane and H‐plane at 60 GHz, respectively. The size of the die of the antenna is 2 mm × 4.5 mm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:155–160, 2014.     

A broadband slant polarized cavity backed microstrip‐fed wide‐slot antenna array

This article deals with the design of a broadband cavity‐backed microstrip‐fed wide‐slot antenna array for L‐band applications. For verification purpose, a sample 1 × 4‐element antenna array has been designed, manufactured and tested. Experimental results have shown satisfactory agreement with the simulation. The proposed antenna array exhibits a measured impedance bandwidth of 1.4 GHz (90%) with frequency of 0.85 to 2.25 GHz and the gain is higher than 11 dBi. The designed antenna has small size and low weight and can be fabricated using a low‐cost fabrication process for easy integration with RF circuits and microwave components. This work is useful for some radar applications and radio frequency identification systems.     

Hepta‐band coupled‐fed antenna for metal‐ring‐frame WWAN/LTE smartphone applications

A small‐size 40 mm × 10 mm coupled‐fed antenna for hepta‐band WWAN/LTE metal‐ring‐frame (MRF) smartphone applications is investigated. Unlike conventional solutions that remove the redundant resonances excited by the MRF, the proposed antenna makes full use of the MRF resonances. By meticulously co‐design the antenna and MRF, multi‐resonance frequencies are excited and integrated, which results in achieving hepta‐band operation for an MRF smartphone antenna. Detail design considerations and experimental results of the proposed antenna are provided and analyzed. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:633–639, 2016.     

A WiMAX circularly polarized antenna array using slot‐coupling feeding technique

In this letter, we present a circular polarization antenna array using the novel slot‐coupling feeding technique. This antenna includes eight elements which are installed in line, each array element is fed by means of two microstrip lines with equal amplitude and phase rotation of 90°. The feeding microstrip lines are coupled to a square patch through a square‐ring slot realized in the feeding network ground plane. With the presence of the slots, this antenna array is able to cover the range of frequency of 3 GHz to 4 GHz. The size of the proposed antenna array is 7λ × 1.8λ × 0.4λ. The measured gain is 15.2 dBi and the bandwidth of S11< ?10 dB is 1 GHz (3–4 GHz, 28%). The antenna array is suited for the WiMAX applications. With the use of slot‐coupling feeding technique, the measured bandwidth for axial ratio < 3 dB is about 24% in the WiMAX frequency band (3.3–3.8GHz). The measured HPBW of the y–z planes is larger than 62°. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:567–574, 2016.     

Dual‐feed full‐metal‐case antenna for WWAN/LTE smartphone applications

A dual‐feed small size full‐metal‐case (FMC) antenna for hepta‐band LTE/WWAN operation in smartphone applications is presented. The antenna proposed here is an integrated part of the full metal case located at the top edge of the smartphone, and it only occupies a small volume of 5 mm × 70 mm × 6 mm. It has two feeding ports that are separately connected to an ON/OFF switch (SW1 and SW2) for controlling the lower and higher operation bands, respectively. For the case when SW1 (ON) and SW2 (OFF), Port‐1 is engaged, and a lower operating band that covers the GSM850/900 operation (824–960 MHz) is achieved. In contrast, Port‐2 will be engaged for the case when SW1 (OFF) and SW2 (ON), and with the aid of a wideband matching circuit, the antenna can induce a higher operating band that can cover the DCS/PCS/UMTS2100/LTE2300/LTE2500 operations (1690–2690 MHz). Detailed design considerations of the proposed FMC antenna are described, and both experimental and simulation results are also presented and discussed. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:595–601, 2016.     

A coplanar‐waveguide‐fed planar integrated cavity backed slotted antenna array using TE33 mode

This short communication presents a substrate integrated waveguide planar cavity slotted antenna array. The proposed antenna array, excited in its TE₃₃ higher mode, incorporates a grounded coplanar‐waveguide (CPW) CPW‐feeding excitation mechanism. The electromagnetic energy is coupled to the air through 3 × 3 slot array etched on top metallic layer. The proposed antenna operates in the X‐band for the frequency range around the 10 to 11 GHz with resonances at 10.4 and 10.8 GHz frequencies. The proposed antenna array was fabricated and tested. Experimental results show good impedance matching with enhanced radiation characteristics, in terms of peak gain, cross‐polarization level, and low back‐radiation. The proposed antenna has the advantages of low‐footprints, lightweight, high gain, low‐cost, and ease of integration with other electronic circuits. With these characteristics, the proposed antenna array can find its applications in compact wireless digital transceivers.     

Millimeter‐wave planar high gain SIW antenna using half elliptic radiation slots

This article reports a high gain millimeter‐wave substrate integrated waveguide (SIW) antenna using low cost printed circuit board technology. The half elliptic slots which can provide small shunt admittance, low cross polarization level and low mutual coupling are etched on the board surface of SIW as radiation slots for large array application. Design procedure for analyzing the characteristics of proposed radiation slot, the beam‐forming structure and the array antenna are presented. As examples, an 8 × 8 and a 32 × 32 SIW slot array antennas are designed and verified by experiments. Good agreements between simulation and measured results are achieved, which shows the 8 × 8 SIW slot array antenna has a gain of 20.8 dBi at 42.5 GHz, the maximum sidelobe level of 42.5 GHz E‐plane and H‐plane radiation patterns are 22.3 dB and 22.1 dB, respectively. The 32 × 32 SIW slot array antenna has a maximum measured gain of 30.05 dBi at 42.5 GHz. At 42.3 GHz, the measured antenna has a gain of 29.6 dBi and a maximum sidelobe level of 19.89 dB and 15.0 dB for the E‐plane and H‐plane radiation patterns. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:709–718, 2015.     

Design of a compact protrudent‐shaped ultra‐wideband multiple‐input‐multiple‐output/diversity antenna with band‐rejection capability

In this endeavor, a new multiple‐input‐multiple‐output antenna with a sharp rejection at wireless local area network (WLAN) band is designed and practically examined for portable wireless ultra‐wideband applications. The intended diversity antenna possess a small size of 15 mm × 26 mm and two inverted L‐strip are loaded over the conventional rectangular patch antenna to form protrudent‐shaped radiator that acts as a radiating element. The sharp band‐rejection capability at WLAN is established by incising the L‐shaped slits at the decoupling structure. More than ?21 dB isolation is accomplished for the complete working band (ie, 2.87 ‐17 GHz). Degradation in the antenna efficiency at the center frequency of band rejection corroborates the good interference rejection capability. The working capabilities of the intended antenna are tested by using the isolation between the ports, total efficiency, gain, envelope correlation coefficient, radiation pattern, mean effective gain, and total active reflection coefficient.     

Ka‐band phased patch array antenna integrated with a PET‐controlled phase shifter

In this article, a 4 × 4 linear‐phased patch array antenna, consisting of four 1 × 4 patch subarrays and a true time‐delay multiline phase shifter, is proposed on a thin film liquid crystal polymer substrate at Ka‐band. The patch antenna is designed with a gain of 6 dBi at 35 GHz and a bandwidth of 23% centered at 35 GHz. To enhance the gain and symmetrize the beam patterns of the 4 × 4 array, a 1 × 4 patch subarray in the E‐plane was designed and characterized. The subarray produces an enhanced gain of 11 dBi and a wide beamwidth of ±38° in the H‐plane for beam steering. The proposed phase shifter comprises a 1 × 4 microstrip line power splitter and a piezoelectric transducer‐controlled phase perturber. A large phase variation of up to 370° and a low insertion loss of less than 2 dB were demonstrated for the phase shifter at Ka‐band. The integrated phased array attains a gain of 15.6 dBi, and a continuous true‐time delay beam steering of up to 33 ± 1° from 31 to 39 GHz. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:199–208, 2016.     

Dual‐band quasi‐self‐complementary antenna for wireless local network operation

This article proposes a compact (6 × 21 × 0.4 mm³) antenna with dual‐band operation that satisfies the wireless local area network. To achieve optimal impedance matching for the lower and upper operating bands, the proposed antenna structure is designed as a quasi‐self‐complementary (QSC) type, in which the lower (2.4 GHz) operating band is excited through the loop‐like structure of the proposed antenna, whereas its self‐complementary counterpart (rectangular patch structure) induces the upper (5.2/5.8 GHz) operating band. Further investigation was also conducted by printing the proposed QSC antenna onto a flexible substrate of 0.063 mm in thickness. To cover both operating bands, the proposed flexible antenna was restructured to 20.5 × 8 mm². The design and initial characteristics of the two proposed antennas were discussed in detail via simulation, and the experimental results showed satisfactory performance of both operating bands. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:298–305, 2014.     

A Dual‐band and dual‐polarized antenna array for 2G/3G/LTE base stations

A dual‐band antenna array is proposed for the application of base station (BS) in 2G/3G/long term evaluation (LTE) mobile communications. This antenna consists of two independent ±45° dual‐polarized arrays, one of which operates from 1.71 to 2.17 GHz, and the other of which is designed from 2.5 to 2.69 GHz. The proposed BS antenna array has a high isolation of greater than 29 dB and high front‐to‐back ratio of more than 26 dB at the operating frequencies. The measured peak gain is 17.9 and 18.1 dBi for the lower and upper bands, respectively, and the cross polarizations isolation (CPI)(within ±60º of the mainlobe) is 16 dB lower than the broadside co‐polarization. It was confirmed that the proposed antenna array meets the communication standards in China. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:154–163, 2016.     

A metallic 3D printed K‐band quasi‐pyramidal‐horn antenna array

A K‐band (18‐27 GHz) antenna array is presented in this article. By deposing the quasi‐pyramidal‐horn upon a print circuit board (PCB), a traveling‐wave quasi‐pyramidal‐horn antenna is formed. Parasitic rings are introduced to decrease the quality factor for an extended bandwidth. The antenna element demonstrates impedance bandwidth 18.6 to 23.3 GHz. The gain is 10.3 dBi at 20.4 GHz with a stable radiation pattern. The impedance bandwidth of a 2 × 2 array is 18.3 to 22.7 GHz, with a maximum gain of 15.2 dBi at 20.4 GHz. The simulated and measured radiation patterns on E‐ and H‐planes at 20.4 GHz agree well. Taking advantage of the 3D printing technology, the quasi‐pyramidal horn is fabricated by selective laser melting using aluminum alloy for time‐saving and process simplicity. The proposed design highlights the hybrid usage of PCB and metallic 3D printing technology in fabricating microwave devices. It is a capable candidate for wireless communication.     

A two‐layer beam‐steering array antenna with 4 × 4 modified Butler matrix fed network for switched beam application

This paper presents a novel two layers beam‐steering array antenna fed by a 4 × 4 modified Butler matrix. Each of the radiation elements have been replaced by a collection of 2 × 2 circularly polarized (CP) square patches, which joined together by a modified sequentially rotated feed network. The antenna array consists of 2 × 5 CP square patches, which connected to four ring sequential rotation and fed by butler matrix. The proposed Butler matrix which plays a role as beam‐steering feed network consists of four novel 90° circular patch couplers and two 45° half circular patch phase shifter. Altogether, using of a 2 × 5 phased array antenna and a modified Butler matrix cause to empower array antenna for covering frequency range between 4.67 to 6.09GHz, the maximum gain of 14.98 dB and 3‐dB axial ratio bandwidth of 1.2GHz (4.9~6.1GHz) is attained.     

An SIW filtering antenna array with quasi‐elliptic gain response based on intercavity bypass coupling

In this article, a filtering antenna array based on substrate integrated waveguide (SIW) is proposed with quasi‐elliptic gain responses for the first time. Two radiation nulls in the gain responses at two sides of the frequency band edges are designed by applying a novel intercavity bypass coupling scheme. First, by carefully analyzing the bypass coupling between the in‐band and out‐of‐band modes in a single oversized TE₁₀₃ mode cavity resonator, quasi‐elliptic filtering responses are achieved for a two‐output filter. Afterward, those cavity resonators coupled with the two outputs are replaced by cavity‐backed slot antennas to achieve the proposed filtering cavity‐backed slot antenna array. Only one cavity is required in our design to achieve the two transmission zeros and the function of power divider. As a result, the complexity of the proposed filtering antenna array is reduced. A prototype operating at Ka band is designed, fabricated and measured with a center frequency of 28.5 GHz and fractional bandwidth of 1.25%. Similar characteristics can be observed between the gain response of the proposed filtering antenna and the transmission responses of the two‐output filter. The proposed SIW filtering antenna array has great potential to be integrated into millimeter‐wave transceiver modules. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:191–198, 2016.     

Reconfigurable bow tie‐based filtering antenna for cognitive radio applications

This article presents the design and implementation of an 88 × 85 mm reconfigurable filtering bow‐tie antenna with four operating states. Two PIN diodes are deployed to reconfigure the transmission zeros to realize ultra‐wide band (UWB), 3.5/5.5 GHz with independent switching. This switching prevents the interference of the primary user into the secondary user thereby making the filtenna suitable for cognitive radio applications. The proposed filtenna consists of a UWB bow‐tie antenna integrated with a band‐pass filter with reconfigurable property enabled using two PIN diodes. The prototype‐filtering antenna is fabricated and the simulated results are validated using measurements. The presented results show that the antenna exhibits good impedance and radiation characteristics.     

Wideband circularly polarized rectangular DRA fed with dual pair of right‐angled microstrip line

In this article, design and development of wideband circularly polarized (CP) rectangular dielectric resonator antenna (RDRA) is presented. To generate wideband CP in proposed antenna, different feeding mechanism have been studied. Three antenna configurations based on different feeding have been discussed using single and dual pair of microstrip lines aligned perpendicular to each other to generate orthogonal modes resulting in circular polarization. It has been claimed here that excitation of RHCP/LHCP field and its direction of radiation could be controlled using height of microstrip feed lines. Finally antenna configuration‐3 is fabricated and measured which shows 36.8% of input impedance bandwidth (3.48–5.05 GHz) and axial ratio bandwidth of 14.46% (3.67–4.24 GHz) in broadside direction (at Φ = 0°, θ = 0°). The final proposed structure exhibits consistent far‐field characteristics with average LHCP gain of 6.4 dB and almost stable radiation efficiency in entire operational frequency range. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:713–723, 2016.     

A cavity‐backed quad‐slot antenna with novel aperture‐coupled feed for circular polarization

This article describes a novel aperture‐coupled feed, for the excitation of a cavity‐backed quad‐slot antenna with circular polarization. Firstly, a quad‐slot cavity‐backed antenna with linear polarization (LP) is proposed. Then, a novel aperture‐coupled feed, which is composed of a cross‐shaped coupling aperture and a T‐shaped feeding microstrip line, will be applied to this LP antenna. By differing the lengths of the four radiation slots together with the novel aperture‐coupled feed, 90° phase difference and equal magnitude between the radiations from the two pairs of slots can be generated. As a result, a good performance of axial ratio will be achieved for the proposed antenna. A prototype is fabricated at Ka band for a demonstration. Investigations show that the antenna can present a minimum axial ratio (AR) of only about 0.37 dB, as well as a fractional AR bandwidth of about 0.94%. A relative high gain of 6.9 dBic at 32.1 GHz is also achieved for the prototype. The proposed substrate integrated cavity backed antenna with circularly polarization has great potential to be integrated into millimeter‐wave transceiver modules. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:588–594, 2016.     

Dual‐band dual‐polarized compact planar monopole antenna for wide axial ratio bandwidth application

In this article, a geometrically simple, microstrip line‐fed planar monopole structure with slanting edge ground plane is designed to realize the dual‐band dual‐polarized operation. The proposed antenna consists of a rotated U‐shaped patch and an electromagnetically coupled L‐shaped parasitic radiating element. Owing to the combination of microstrip line‐fed radiating patch and a slanting‐edge rectangular ground plane on the opposite side of the substrate, the proposed dual‐band antenna can generate broad axial ratio bandwidth (ARBW) in the upper frequency band. The overall dimension of the prototype is only 32 × 32 × 1.6 mm³. The measured results validate that the proposed antenna has two operational frequency bands, 29.84% (1.54‐2.08 GHz) for linearly polarized radiation and 71.85% (3.96‐8.4 GHz) for circularly polarized radiation. Measured result shows that 3‐dB ARBW of the proposed antenna is 73.54% (3.80‐8.22 GHz) in the higher frequency band. It shows that the higher frequency band exhibits a left‐hand circularly polarized radiation in the boresight direction.     

Miniaturized coplanar waveguide‐fed disk monopole antenna for ultra‐wideband applications with improved wireless local area network band rejection

In this article, we first propose a miniaturized coplanar waveguide‐fed disk monopole antenna with overall size of 14 mm × 22 mm. Measurement results show that the antenna has an ultrawide impedance bandwidth from 3 to 12 GHz and omnidirectional radiation pattern. Next, we introduce two U‐shaped slots in the ground plane of the antenna to provide an improved band rejection in the wireless local area network frequency band. Experimental results indicate that the proposed band notch antenna has maximum voltage standing wave ratio (VSWR) of 25 in the desired rejection band. Measured gain for the proposed band notch antenna is around 0 dB and reduces to ?15dB in the desired rejection band. Time domain performance of both the initial antenna and band notch antenna is also examined and the best detection template is presented. Computed total fidelity factors for both the initial and band notch antenna are greater than 0.9. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013     

A high‐isolation dual‐polarized quad‐patch antenna fed by stacked substrate integrated waveguides for millimeter‐wave application

A high‐isolation dual‐polarized quad‐patch antenna fed by stacked substrate integrated waveguide (SIW) that is suitable for millimeter‐wave band is proposed in this paper. The antenna consists of a quad‐patch radiator, a two‐layer SIW feeding structure and two feeding ports for horizontal and vertical polarization. The two‐layer stacked SIW feeding structure achieves the high isolation between the two feeding ports (|S₂₁| ≤ ?45 dB). Based on the proposed element, a 1 × 4 antenna array with a simple series‐fed network is also designed and investigated. A prototype working at the frequency band from 38 to 40 GHz is fabricated and tested. The results indicate that the proposed antenna has good radiation performance at 38 GHz that covers future 5G applications.