Study on the Influence of Inserting Clearance on the Voltage Standing Wave Ratio in RF Connector

RF (Radio Frequency) connector has been extensively applied in the field of communication for it is a key device of transmitting microwave signals. If he RF connector end is designed improperly in dimension, a clearance will be observed after inserting, resulting in an abnormal phenomenon in the voltage standing wave ratio (VSWR) of the RF connector. This paper studied the influence of the inserting clearance of RF connector on the voltage standing wave ratio through theoretical analysis and performance simulation. Moreover, the solution to the abnormal voltage standing wave ratio was also proposed. At last, the abnormal phenomenon of voltage standing wave ratio of the connector in the inserting process was handled by means of carrying out optimization design and test validation on the RF connector.

AN ANTENNA BASED ON A HYBRID METAL–DIELECTRIC STRUCTURE

Purpose: Nowadays, in the millimeter frequency range, the dielectric waveguides of various modifications have certain advantages over the standard metal waveguides, primarily due to the possibility of creating functional units based on them. This is due to the relative simplicity and low cost of manufacturing the dielectric waveguides and functional units using them, the high degree of their integration with active elements, the use in their manufacture of different dielectrics and polymers with a wide range of material constants and a variety of mechanical properties (in particular, some materials have a significant flexibility). After making a series of physical experiments we have found the possibility of implementing the frequency selection and radiation into free space of electromagnetic waves by a hybrid metal-dielectric structure. Design/methodology/approach: The studied electrodynamic structure belongs to the class of hybrid metal-dielectric structures. It includes a modified inverted dielectric waveguide with a periodic sequence on the dielectric plate of fifteen dielectric rods with metallized coating on one of the faces placed outwards. The structure efficiency was estimated by the voltage standing-wave ratio (VSWR) values and power attenuation in the duct. The measurements were made with the reflectometer method. To estimate the degree of electromagnetic field concentration near the rod inhomogeneities in the near zone, the mobile probe method was used. The field structures were visualized with the method of isolines. Findings: The results of a series of experimental investigations showed the possibility of matching the structure with the external waveguides in the frequency range of 26.5-32.5 GHz with the voltage standing-wave ratio (VSWR) less than 1.8. The frequency dependence of attenuation is oscillatory with clearly expressed frequency ranges with small and large attenuation values. Moreover, the dependence is almost periodic, which is typical of periodic structures. The frequency response slope in the transition zones can be quite high and reach values of 41.26 dB/GHz. The degree of concentration of the electric field near the waveguide dielectric rod and the degree of excitation of the dielectric inhomogeneities was found by directly measured electric field strength in the near zone. Measurements of energy characteristics made under the short-circuit conditions for the main guide and in the mode of matched load of the main guide showed both the ability to control the polarization characteristics and the ability to change the appearance of the pattern and its orientation in space. Conclusions: It has been experimentally proven that a hybrid metal-dielectric structure, being a modified inverted dielectric waveguide with a periodic sequence on the dielectric plate of fifteen dielectric rods with metalized coating on one of the faces placed outwards, can be effectively integrated into a standard transmission line. It is found that this structure can be matched with the external circuits in a fairly wide frequency range. It is also found that in different frequency ranges this hybrid metal-dielectric structure shows the possibility of both efficient frequency selection and radiation in free space. Antenna measurements have shown the beam pattern shape controllability. Key words: inverted dielectric waveguide, periodic sequence, voltage standing-wave ratio (VSWR), attenuation, reflectometer method, mobile probe method, directivity pattern

Bi-Ellipse Microstripline Antenna Array Varians

The objectives of this research include obtaining and verifying the impedance formula of the designed bi-ellipse microstrip antenna and correlating the results obtained through simulation and experimentation. The research also aims to obtain the structure and dimensions that provide optimal characteristics of the designed bi-ellipse microstrip antenna and produce a prototype at S, C and X-Band frequencies. This research produced the structure and dimensions of a bi-ellipse microstrip antenna that provide optimal characteristics of antenna. The characteristics results of the antenna parameters in this research include a 8x2 array, with a bandwidth value of around 100.0 MHz obtained at a working frequency of 7.09GHz (7.04 GHz - 7.14 GHz), with a reflection coefficient value of 0.02, Voltage Standing Wave Ratio (VSWR) of 1.06, return loss of −30.00 dB and a gain of 7.30 dB. For the 8x4 array, a bandwidth value of approximately 210.0 MHz is obtained at a working frequency range of 2.85GHz, which ranges from 2.74GHz - 2.95GHz, with a reflection coefficient value of 0.04, Voltage Standing Wave Ratio (VSWR) of 1.09, return loss of −27.06 dB and a gain of 8.19 dB. The results presented above fulfill the indicators of good antenna characteristics parameters applicable to radar communication systems.

Design and Analysis of a Frequency Reconfigurable Penta-Band Antenna for WLAN and 5G Applications

This paper presents a discussion on a low-profile, frequency-reconfigurable penta-band antenna. This antenna consists of two asymmetric L-shaped rectangular patches electrically connected by a single PIN diode. The proposed antenna operates at five frequency bands depending upon the switching states of the PIN diode. It operates at 2.4 GHz (WLAN) and 5.3 GHz (5G) during forward bias of the diode, 3.3 GHz (5G) and 5.9 GHz (WLAN) during reverse bias of the diode and 4 GHz during zero bias condition providing a wide bandwidth (3.6–4.8 GHz) at this state. The antenna has voltage standing wave ratio (VSWR) ranges from 1 to 2, gain value ranges from 2.6 to 5.0 dBi, and a maximum radiation efficiency of 85%. This antenna can be integrated with modern devices such as smart phones, laptops, and other handheld devices due to its simplistic geometry. A prototype of the model is fabricated, and the results are validated.

On the 5G Communications: Fractal-Shaped Antennas for PPDR Applications

In this study, one method of using antennas based on fractals to cover few kinds of public protection and disaster relief (PPDR) communications was presented. Dedicated antenna forms, necessary for antenna design by 5G implementation, were enhanced to suit the requirements of specific applications. Employing fractal-shaped antennas have allowed us to accomplish all these actions, which request compact, conformal, and broadband high performance devices. Antennas derived from Koch’s curve fractals are studied. In order to implement PPDR communications in 5G technology, frequency bandwidths of importance have been carefully selected and properly included in the antenna developments under MATLAB environment. Important information necessary for antenna designers, such as 360 degrees directivity at various frequencies, the impedance (resistance and reactance) along the bandwidth of interest, as well as voltage standing wave ratio (VSWR) along the bandwidth of interest for dipole, one-iteration, and two-iteration Koch’s curves, respectively, have been obtained. The characteristic of directivity at selected frequencies is also highlighted. In order to maximize antenna parameters, this study has successfully proposed using fractal antennas, objects that use self-similarity property of fractals for optimum operation in several frequency ranges. For the studied antennas, we have obtained the following results regarding the maximum gains in dBi (which is the unit of the ratio between the gains of the antenna compared to the gain of an isotropic antenna). For the dipole antennas, the gains are 2.73 dBi and 4.76 dBi at 460 MHz and 770 MHz, respectively. The gains for one-iteration fractal Koch antenna are 6.91 dBi and 4.51 dBi at 460 MHz and 770 MHz, respectively, and finally, for two-iteration fractal Koch antenna, the gains are 4.91 dBi and 3.28 dBi at 460 MHz and 770 MHz, respectively. Moreover, the impedance along the bandwidth is approximately 360 Ohms for two-iteration fractal Koch antenna, 180 Ohms for one-iteration fractal Koch antenna, and 140 Ohms for dipole antenna, respectively.

Fabrication of Horn Antenna for Microwave Application

This paper contains a novel design of a horn antenna control system for microwave applications. Using “Fermat’s principle” the horn antenna is designed and fabricated. For microwave applications, high gain and low voltage standing wave ratio(VSWR) is needed, so for that purpose horn antenna is fabricated. In a previous paper, they designed the Yagi Uda antenna which is used for multiple driven elements by the method called maximum power transmission efficiency. For multiple driven elements, the horn antenna cannot be fabricated. If suppose yagi uda is fabricated using the principle called Fermat's, the system can't achieve more gain and low voltage standing wave ratio. Yagi uda antenna can achieve only a high voltage standing wave ratio. To reduce the problems in the existing paper, our paper designs a horn antenna to achieve high gain and low voltage standing wave ratio( VSWR) which is used for microwave applications to transmit microwaves from a waveguide out into space or collect microwaves into a waveguide for the reception.

A Compact Wideband Dual-Circular Polarization CPW-Fed Slot Antenna

A compact wideband coplanar waveguide (CPW) excited slot antenna with dual-circular polarization (DCP) is presented and fabricated in this paper. Two inverted-L-shaped patches are implanted in a square slot to achieve wideband DCP characteristic. The feed line is terminated on an inverted-L-shaped patch. Moreover, two rectangular slots are added on the corners of the antenna to improve the bandwidth of axial ratio (AR) and the voltage standing wave ratio (VSWR). The simulated results show that the designed antenna can generate a good impedance bandwidth of 70.4% and a 3-dB AR bandwidth of 48.6%, respectively. This antenna possesses the qualities of small size, simple structure, and good dual-circular polarization.

Impedance Matching Simulation for Microstrip Antenna on Frequency 3.4-3.7 GHz Using Double Stub

Impedance matching is an attempt to adjust the antenna impedance with the characteristic impedance of the transmission line. Impedance matching has functions to avoid reflected power from the antenna so that power cannot be received by the receiver. In this study, impedance matching was used double stub. The voltage standing wave ratio (VSWR) indicates how well the impedance matching is made. Simulation of this impedance matching will use to microstrip antenna on frequency 3.4 – 3.7 GHz. CST Studio Suite is used to simulating the antenna microstrip with double stub. Based on the result, this research shows that VSWR and return loss in single and double rectangular microstrip antenna have a better value if use impedance matching than without using impedance matching.

Rancang Bangun Antena Mikrostrip Patch Serangga untuk Aplikasi Monitoring Komposter pada Frekuensi 2,4 GHz

Komposter merupakan alat untuk menampung kompos. Kompos sangat dibutuhkan oleh masyarakat khususnya yang gemar bercocok tanam. Dengan adanya alat monitoring komposter ini memudahkan masyarakat untuk mengecek suhu dan kelembapan dari kompos. Data suhu dan kelembapan dari kompos dikirimkan dari bagian pengirim ke bagian penerima menggunakan sebuah antena mikrostrip dengan bentuk patch serangga. Antena mikrostrip patch serangga bekerja pada frekuensi 2,4 GHz. Antena mikrostrip patch serangga merupakan pengembangan dari patch rectangular, sehingga dalam perhitungannya menggunakan rumus dasar antena patch rectangular. Perancangan dan simulasi antena dilakukan menggunakan software CST Studio Suite 2018. Simulasi dilakukan dengan melakuakn percobaan mengubah dimensi antena sehingga didapatkan hasil parameter yang terbaik. Parameter antena yang diukur adalah Voltage Standing Wave Ratio (VSWR), return loss, gain, dan pola radiasi. Hasil pengukuran parameter antena yang diperoleh yaitu VSWR sebesar 1,0772, return loss sebesar -28,5954 dB, gain sebesar 4,249 dB, dan pola radiasi bidirectional.