Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> The most-up-to-date resource available on antenna theory and design. Expanded coverage of design procedures and equations makes meeting ABET design requirements easy and prepares readers for authentic situations in industry. New coverage of microstrip antennas exposes readers to information vital to a wide variety of practical applications.Computer programs at end of each chapter and the accompanying disk assist in problem solving, design projects and data plotting.-- Includes updated material on moment methods, radar cross section, mutual impedances, aperture and horn antennas, and antenna measurements.-- Outstanding 3-dimensional illustrations help readers visualize the entire antenna radiation pattern. <s> BIB001 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> In this letter, we demonstrate the gain enhancement of an ultrawideband (UWB) antenna, achieved using an appropriately designed multioctave dual-layer frequency selective surface (FSS) reflector. The proposed novel FSS reflects effectively in phase over a bandwidth of about 120%. Hence, significant enhancement in antenna gain has been achieved with a low-profile configuration without compromising the impedance bandwidth of the UWB antenna. The proposed FSS reflector has a low transmission coefficient and linearly decreasing phase over an ultra-wide frequency band, which is the key requirement for providing an effectively in-phase reflection at the antenna plane. The composite structure is compact, with a total height of λ/4, where λ is the free-space wavelength at the lowest operating frequency of 3 GHz. Experimental results show an impedance bandwidth of 122%. The antenna gain is maintained around 7.5 dBi from 3 to 7 GHz. Between 7-14 GHz, the antenna is more directive with a gain of about 9 dBi with ±0.5 dB variation. Experimental measurements con firm the predicted wideband antenna performance and gain enhancement due to the FSS reflector. <s> BIB002 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> AbstractA microstrip-fed ultra-wideband antenna with dual band-rejection characteristics is investigated. The antenna has the same shape between radiation patch and ground plane, and is fabricated on a Rogers RT/duroid 5880 substrate with an overall size of 22×31.85×0.508 mm3 . To generate two notched frequency bands, a U-shaped parasitic element on the back of the patch is utilized. The two notched bands can be controlled by adjusting the size of the parasitic element. The measured results show that the proposed antenna has an impedance bandwidth of 3.0 to 11.7 GHz for S11 <蜢10 dB, expects two eliminated frequency bands 5.08~5.96 GHz for wireless local area network and 8.71~10.25 GHz for X-band. <s> BIB003 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> In this paper the design of an ultra-wideband (UWB) monopole antenna with a coplanar waveguide (CPW) feed for ground penetrating radar (GPR) application is presented. The antenna offers a broad bandwidth from 0.4 to 3 GHz with a relative small GPR antenna size compared to the conventional circular monopole antenna. The other advantages of such an antenna are the simple antenna structure and easy to be integrated with PCB board. A rectangular conducting reflector is placed below the antenna to obtain a unidirectional radiation pattern for GPR application. Computer simulations are conducted and measurements are carried out to validate the results. <s> BIB004 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> Novel planar Vivaldi antenna with better performance compared to conventional TEM horn antenna is introduced. An exponential tapered slot edge (TSE) structure is employed. Electromagnetic band gap structure as seven pair of loop or square shaped defected ground structure is added to the ground antenna plane. The proposed shape has the advantage of extending the low-end bandwidth limit due to improving the antenna matching especially at low frequency and reduced the electrical length of the antenna by 45% compared to the original antenna size. <s> BIB005 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> A printed planar antenna having a compact dimension of 27×23.5 mm2, fed by a microstrip line is proposed in this article. The proposed compact antenna consists of a circular disc radiator and partial ground plane with a rectangular slot on its' top edge. Experimental results show that the antenna has an ?10 dB impedance bandwidth ranges from 3.3 GHz to 20 GHz (193%) which almost covers the entire UWB band. A symmetric and stable radiation pattern with an average realized gain of 5.11 dBi makes the proposed antenna suitable for using in different UWB applications. Details of the proposed antenna design are presented and discussed. <s> BIB006 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> A modified design of an ultra-wide band antenna (UWB) using stepped feed, partial slotted ground, two level stairs with notches in patch and ground plane is simulated with band rejection feature. The enhanced frequency range (3.2 to 14.0 GHz) is covered by the proposed antenna with the overall dimensions of 25.0 (L) x 20.0 (W) x 1.60 (H) mm3. The voltage standing wave ratio (VSWR) is less than 2.0 for entire operating frequency range. The proposed antenna operating on 5.2/5.8 GHz wireless local area network (WLAN), 3.5/5.5 GHz WiMAX, X-band and partial range (12.0 to 14.0 GHz) of Ku-band finds its applications to secure military communication, radar, medical applications and home appliances. <s> BIB007 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> A new ultra-wideband antenna with enhanced and nearly constant gain is presented. This quasi-planar antenna is composed of a CPW-fed printed monopole and a short horn, both made out of a single substrate. The measurements demonstrate an almost ∞at peak gain of 5:5dBi § 0:7dB from 2.5GHz to 15GHz with the average gain difierence in XZ plane is roughly 2dB up to 8GHz, which further rise to 6dB at 10GHz. The antenna also has a nearly linear phase response in this band. Well tested performance both in frequency and time domains, along with broad azimuth pattern, results in minimal ringing of a radiated pulse. The new antenna is suitable for establishing good line of sight link for UWB transmission and other broadband applications. <s> BIB008 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> In recent years Cognitive radio and UWB technologies are emerging for efficient use of Spectrum for short range wireless communications. FCC also has released a wideband of 7.5 GHz (From 3.1GHz to 10.6GHz) as unlicensed to use it anytime anywhere. In cognitive radio for sensing purpose and in UWB transceiver, UWB antennas play a vital role. Since antenna dimensions are frequency dependent, designing an antenna for wideband is a challenging task. This paper discusses the step by step techniques to obtain ultra wide bandwidth (2.23GHz-11.4GHz) from narrowband patch antenna. Also it discusses the various antenna parameters of proposed antenna design, its simulated and experimental results. <s> BIB009 </s> Ultra-Wideband Antenna Design for GPR Applications: A Review <s> D. Planar Antenna <s> In modern wireless communication, UWB applications are becoming very popular because of reliable, secure and high speed data transmission over smaller distances. In these applications, it is very much essential to have small size printed antennas for transmitting and receiving of UWB signals. However, designing small size printed antennas with good performance is quite a challenging task. In this paper, we discuss performance characteristics of a simple and small size planar monopole antenna for UWB applications. Proposed UWB antenna is covering 10dB return loss frequencies ranging from 2.72GHz to 12.68GHz. This design is achieving a maximum gain of 5.24dBi at 9.25GHz and a maximum efficiency of 96.45% at 3.1GHz. This paper also discusses a reason of enhancement in gain and efficiency reduction at higher frequencies along with UWB antennas requirements. Proposed design dimensions are 30mm×30mm×1.6mm with FR-4 as a dielectric substrate. Because of small size and good performance, proposed UWB antenna can be used in many applications like 4G, wireless body area networks, spectrum sensing in cognitive radio, wireless telemetry, telemedicine and RF energy harvesting. Experimental result shows that, there is a good agreement between the simulated and measured antenna results. <s> BIB010
A planar antenna, as shown in Fig. 4 , is a popular candidate for UWB due to its simplicity, conformity in design, cost effectiveness and light weight properties BIB001 , BIB003 . A planar antenna mainly consists of a radiating patch and either a full or partial ground plane with a defected ground structure (DGS) BIB005 which can be varied according to the www.ijacsa.thesai.org design requirement. The length, L and width, W of the patch can be determined from (7) and (8) BIB001 , BIB007 : Where: In  , a hexagonal fractal patch antenna is proposed to achieve a wideband characteristic. The design is modified by iteration of hexagonal fractals with slits in the ground plane to create a notch that affects the impedance bandwidth. Hexagonal slots are also introduced in the patch and slots in the ground plane alongside the slits. A modified circular patch antenna for UWB GPR applications is proposed in BIB004 . The conventional circular disc is modified to produce a mickey-shaped patch radiator with a CPW feed. The substrate used is FR-4 with Ԑr of 4.3. A rectangular copper reflector is inserted below the antenna to make it directional. Another circular disc antenna is designed in BIB006 to improve the impedance bandwidth and efficiency of the planar antenna. A rectangular slot is introduced at the edge of the ground. A stepped feeding and two level notched stairs in the patch with a partial ground plane over Rogers Duroid RT-5880 with a dielectric constant, Ԑr of 2.2 are included in the design of an UWB planar antenna in BIB007 . The antenna is tested in step-bystep basis. Firstly, the antenna is simulated and tested only with a simple rectangular patch and a partial ground followed by a stair patch and a partial ground. Finally, the stubs are introduced in the stairs feed patch for band notch. A multioctave frequency selective antenna with a reflector is proposed in BIB002 to study the gain performance. Fig. 4 . A planar antenna BIB007 . An UWB quasi-planar antenna in BIB008 is designed for gain enhancement. The antenna consists of a CPW-fed semicircular disc monopole antenna with a short horn. The shape of this quasi antenna makes it a potential candidate for GPR technology. A quadruple-band planar antenna is developed in  . This is a simple microstrip patch antenna with four slots of different geometries namely, square, rectangle, circle and ellipse. Similarly, another slotted monopole planar antenna with a key shape is designed in BIB010 where the shape is achieved by etching two symmetrical curved slots in the circular patch which in return, increases the efficiency of the antenna. A spanner-shaped antenna is proposed in BIB009 which is achieved by cutting a rectangular slot on the upper side of minor axis in an elliptical-shaped antenna to improve the gain and bandwidth for GPR applications.