In order for a mobile phone to place or receive a phone call, it must acquire signal from a cellular tower. Many factors including the environment (such as trees or buildings), distance between the smartphone and the tower, and wireless carrier network congestion negatively impact the received signal strength. A dropped call or inability to place/receive a call occurs when the signal strength drops low enough that the smartphone and tower can no longer communicate with one another. More than 70 percent of smartphone users have trouble maintaining cell phone signal strength throughout their day.

Traditional cellular signal amplifiers cost hundreds to thousands of dollars and are typically placed in a permanent location inside a car, home, or office to improve signal. They often require expensive professional installation and carrier registration. At mJoose, we developed the first truly mobile and affordable amplification system enclosed inside a smartphone case. The mJoose case is able to receive signal that is too low for the smartphone to receive on its own. The mJoose case contains patented, third party tested and certified technology that creates a better handshake between the cell phone tower and your smart phone.

We designed and built the system using our decades of experience in radio frequency technology. The product was then subjected to rigorous testing that met or exceeded Government and industry standards. The mJoose patented antenna system is the first of its kind to be third party tested by Cellular Telephone Industries Association (CTIA) certified laboratories, approved by the Federal Communications Commission (FCC) in the United States, Industry Canada (IC) in Canada and Instituto Federal de Telecomunicaciones (IFT) in Mexico. The iPhone 6 and 6s cases have also been accredited by the Apple MFi (Made for iPhone) program.

The mJoose case is guaranteed to provide mobile professionals with the following key benefits:

·         Amplifies cellular signal ·         Improves internet connectivity
·         Increases battery life and charging speed ·         Reduces electromagnetic radiation






Up to 100x Signal Strength (20 dB Gain) 


The mJoose case includes an active antenna system that provides up to 100x signal strength gain. This has been independently tested by SGS Inc., the world’s leading inspection, verification, testing and certification company. SGS is a CTIA certified test lab and FCC authorized third party lab. The iPhone 6 and 6s product has also been Apple MFi certified which included passing their Over-The-Air (OTA) testing requirement. This test was conducted by the Apple authorized lab, Underwriters Laboratories, Inc. (UL), which is also a CTIA certified OTA testing lab. UL is a global leader in testing, inspection, certification, auditing, and validation. More than 2 billion products receive the UL certification annually, making it the single and most accredited mark in the United States.

The purpose of OTA testing is to evaluate the TRP and TIS (total radiated power and total isotropic sensitivity) of cell phones. An assessment was conducted in an anechoic chamber as shown in Figure 1. An anechoic chamber is a room designed to completely absorb reflections of either sound or electromagnetic waves. It is also insulated from exterior sources of noise. This guarantees the performance of the device under test can be evaluated in a clean environment. A communications test set (also referred to as a “call box”) was used to emulate a base station (cell tower) and communicate with the cell phone by voice or data using the mJoose case. For cell phones, 2G/3G/4G protocols have to be tested because of their different system parameters (such as transmitter/receiver powers and modulations). Figure 2 illustrates the OTA / Signal strength test configuration.


Figure 1. OTA testing of mJoose case with the host phone in SGS R&S TS8991 3D anechoic chamber 

Figure 2. System block diagram of OTA and signal strength testing. (Source: mJoose): the cellular signal is carried to mJoose device from a base station simulator (i.e. cellular tower (1)) through a transmit antenna (2), collected into vertical-polarized and horizontal-polarized radio waves through a receiving antenna (3), amplified and carried to a base station (1) and spectrum analyzer (4). The mJoose device is placed on the positioner (i.e. mannequin hand and body effect (5)) within an anechoic chamber (6) that eliminates outside noise as pictured below in Figure 2.



Better uplink / downlink speed in poor signal coverage


Throughput rate specifies how many units of a data package a communication system is able to process in a given amount of time. It measures the speed at which a specific workload can be completed and its response time. This throughput rate was tested by MobileNet Services Inc., an RF engineering service company specializing in field test and analysis for both cellular and non-cellular network providers. Two identical phones (one with the mJoose case and one without) were moved throughout various poor cell service locations. An improved signal strength and throughput data rate (faster downloading speed) was observed on the device using the mJoose case (Figure 3). Stationary CDF Comparison Charts confirmed the findings of the better RSVP rates (Figure 4).  


Figure 3. iPhone with mJoose case displays consistently better RSRP (reference signal received power) value throughout stationary testing.


Figure 4. Stationary CDF comparison charts of downlink throughput rate (with and without mJoose case attached).



120% more battery life / 1.5x faster charging


The iPhone 6/6s battery capacity is 1810/1750 mAh. The mJoose case includes a 2950 mAh battery, therefore extending the phone’s charge capacity by up to 120% (Figure 5). This provides users over twice as much time to surf, talk and text.

An iPhone charger provides 1 Amp of current to the smartphone. The mJoose case supplies 1.5-1.6 Amp current. Testing performed at mJoose showed up to 1.5X charging speed compared to a standard iPhone wall charger. This fast charging allows users to spend less time waiting for their phone to charge. Customers have also reported that while using the mJoose case they can go for up 2 days without needing to re-charge their phones with a wall charger.

Figure 5. iPhone 6 and mJoose case batteries.





Reduced by an average of 70%


Specific Absorption Rate (SAR) measures the rate of radio frequency (RF) energy absorbed by the human body. The FCC’s exposure limit is set at 1.6 watts per kilogram (1.6 W/kg) in SAR and a cell phone’s rating cannot exceed this limit in order to receive FCC certification and be sold in the United States (“Specific Absorption Rate (SAR) for Cellular Telephones” Federal Communications Commission. N.p., 30 Nov. 2015. Web. 06 Dec. 2016). Testing is also conducted with accessories that may impact the SAR rating of the bare smartphone. SAR testing of the mJoose phone case was performed by the RF Exposure Lab, LLC., a SAR testing and calibration lab with A2LA accreditation.  The same cell phone was tested with and without the case while operating at its highest power level and held in various positions against a phantom head and body (Figure 6). The phantom head/body was filled with liquid as to simulate human tissue and a robotic probe measured the SAR.

Figure 6. SAR testing: (a) Speag DASY system; (b) right touch end view with mJoose case attached to iPhone.

Figure 7 displays the SAR plot results when the smartphone is tested as shown in Figure 6. In Figure 7(a) the relatively strong electric field is distributed around the cheek (i.e. the phone radiates directly towards the head). When the mJoose case is attached to the host phone, the radiation peak changes direction and the electric field is reduced as shown in Figure 7(b).

Figure 7. Head SAR plot of an LTE Band: (a) host phone only (b) host phone with the mJoose phone case attached. Peak SARs decreased from 0.289 to 0.128 (W/kg) with the case attached.

Figure 8 displays the SAR plot results with the device placed next to the body phantom (shaped like an elliptical sink). With the mJoose case attached to the host phone, the phone is sandwiched between the body phantom and the phone case. In Figure 8(a) the electrical field is focused on a hotspot and the SAR value is high (0.882 W/kg). With the mJoose case attached, the surface current of the device is distributed throughout a larger area and the electrical field has a more uniform strength and hence a lower SAR value (0.288 W/kg). Using 2G, 3G, and 4G protocols the electromagnetic radiation of SAR was shown to be reduced by an average of 70% with the mJoose case attached.

Figure 8. Body SAR plot of an LTE Band: (a) host phone only (b) host phone with the mJoose phone case attached. Peak SARs decreased from 0.882 to 0.288 (W/kg) with the mJoose case attached.



The mJoose technology has passed all required testing to be certified by the North American governmental telecommunication organizations: FCC in the United States, IC in Canada, and IFT Mexico. As a part of these certifications, Electromagnetic Compatibility, Specific Absorption Rate, and Hearing Aid Compatibility testing was required.

1.  Electromagnetic Compatibility (EMC) testing was performed by NEMKO Ltd. to confirm that the mJoose case did not interfere with the host phone or with other electronics in its environment. Figure 9 displays the chamber in which EMC testing was conducted. The testing was completed in a closed room with an antenna that detected unwanted radiation. The case was exposed to a radiated field to observe whether it disrupted the phones function when connecting to a wireless network. The outgoing radiation was also measured to see if the mJoose case caused interference to other devices. The results of this emission radiation testing indicated that the mJoose case did not interfere with any neighboring devices and worked as intended in its surrounding environment.

Figure 9.  EMC testing set up.

2. Specific Absorption Rate (SAR) testing is a required radio frequency (RF) exposure evaluation to measure the rate of energy absorption by the human body. Details of the SAR testing performed by RF Exposure Lab, LLC., and SAR analysis are described in the “CELLULAR RADIATION” section above and referenced in Figures 7 and Figure 8.

3. Hearing Aid Compatibility (HAC) testing was performed by SGS, Inc. to safeguard that the mJoose case did not interfere with hearing aids or change the cellphones “T3” (or “U3T”) rating. It was also tested to ensure that it did not change the ratings of hearing aids from M1 to M4, with M1 being the least immune to RF interference and M4 the most immune under the ANSI standard. The mJoose case passed this testing and was found to cause no interference or impact to the hearing aid.



The mJoose mobile signal amplifier is more than just a case. It contains a sophisticated antenna system that safely delivers amplified cellular signal, improved internet connectivity, better battery life/charging speeds and reduced electromagnetic radiation. It was designed by a team of radio frequency engineering professionals and tested by globally recognized third parties. It has been certified by governing bodies for use throughout North America on any wireless carrier network. The mJoose case contains disruptive technology that revolutionizes the cellular signal amplification category. It provides smartphone users with truly mobile freedom to receive signal throughout their day without the added expense and hassle.